Practical Fishkeeping 2018-12.pdf

Electric fish with a long trunk! Advice 21

COMMON MISTAKES

PIRANHA! Ambush predators

Tanganyika’s ‘gobies’

Secret lives of Jawfish

HANDSOME HALFBEAKS Meet the longest chins in fishkeeping

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THE EXPERTS

STEVE BAKER

Steve has been getting stuck in to the world of piranhas, as well as listing some of the common errors fishkeepers make. See if you’re making any on page 74.

GABOR HORVATH Gabor has been doing what he does best – breeding and photographing fish in his fish house. This month it’s halfbeaks, and you’ll find them on page 50.

NEIL HEPWORTH

NEALE MONKS We asked Neale to tell us all about what we can stick on the bottom of our tanks, and what a result! Find out all about different substrates on page 70.

AD KONINGS We tasked Ad with delivering some of his vast knowledge on Goby cichlids. After a lifetime of study, he can share some revelations with us on page 98.

DAVE WOLFENDEN Dave has been investigating the world of elephantnoses. Learn about the fascinating lives of these snouty mormyrids on page 78.

CHRIS SERGEANT Chris has delivered yet another masterpiece, this time all about ambush predators in the underwater world. Find out the sneaky fish with the fastest and biggest bites on page 28.

‘SHNAUZENORGAN’ MAY well be my new favourite word. I never even knew it existed until I read about it this month, and then it made me realise how this hobby is riddled with cool facts – cool facts and cooler-sounding words. Did you know, for example, that elephantnose have the heaviest brain to body ratio of any animal on Earth? We used to think it was us humans that packed the biggest brains, but it turns out we got trumped by fish. As for other awesome words, I’m reminded of ‘schreckstoff’ which I came across a few years ago when researching pain and stress. It turns out that when some fish are hurt they release a chemical that acts as a warning to others not to get near, and that’s the name of the chemical. Anyway, enough about me. What new words are you learning this month? Let me know. Letters please!

Nathan Hill, Associate Editor

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Red bellied piranha. Photograph by AmazonImages/Alamy

Which fish clings to a rock af it has died? Find out on page 22

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22 scientist goes about setting up a flowing stream tank for agile hillstream loaches.

INSPIRATION

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RARE BEAUTY The Crystal rainbow tetra is still something of a mystery to science, but it’s pretty as a stained glass window.

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ELECTRIC ELEPHANTS

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JAWS

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JEWEL OF AFRICA

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‘GOBIES’ OF LAKE TANGANYIKA

THE ART OF THE AMBUSH A captivating look at aquatic ambush predators of all shapes and sizes, and the specialised strategies they’ve developed to catch their prey.

BITING FOR THEIR LIFE Its reputation precedes it, but is the Piranha an aggressive, cold-blooded predator or a much misund softy?

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Editor’s Pick

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With their bigger-than-average brains and peculiar trunk-like snouts, elephantnoses are simply unforgettable. Oh, and they’re electric too!

Packed with personality, meet the colourful, diverse, burrow-dwelling members of the jawfish family.

THE RUMMY-NOSE TRIO As a perennial old favourite, Rummynose tetra are sometimes overlooked, but these three little ‘Rudolphs’ are well worth a second glance.

HAPPY HALFBEAKS Distinctly odd-looking, slender Wrestling halfbeaks are highly recommended if you want to keep (and breed) something just a little bit different.

Read editor Nathan’s favourite article this issue: Rumeynose tetra PAGE 44

Let’s hear it for Pelvicachromis subocellatus, the lovely but lesser-known cousin of the Rainbow kribensis.

Cute as a button, these attractive little fishes’ shared parenting behaviour is fascinating to watch.

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THINGS YOU WILL LEARN IN THIS ISSUE

1

The incredible speed of the Bluestripe pipefish when it’s in hunting mode

2

The uses of different kinds of substrates and how to prepare them.

3

How to tackle the problem of feeding your fish when you go on holiday. What are your options?

4

That a piranha sheds its teeth in sets, a quarter at a time.

14 diffuser set from Colombo and a Vultron airpump. Plus a look at three brands of polymer balls – are these spheres the future when it comes to maturing your pond?

NEWS & VIEWS

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AQUATIC NEWS Fascinating deep-sea species discoveries, ecstatic octopuses, speedy sharks and a tribute to the late Jack Wattley, the ‘godfather of Discus’.

ETHICAL DEBATE PFK associate editor Nathan Hill and staff writer Steve Baker go head to head on the question of water testing.

LETTERS

REGULARS

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Thoughts from a young fishkeeper, biotope snobbery and in praise of live food.

GEAR & REVIEWS GUIDE 108 GEAR 66 The latest fishkeeping products reviewed, including a CO 2

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The voltage that an ‘electric’ elephantnose will give off if you touch it.

86 Practical Fishkeeping delivered to your digital device

up three different popular canister filters.

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KNOW-HOW: ALL ABOUT SUBSTRATES From silica sand to aquatic soil, what’s the best type of substrate for your plants and your livestock?

PAGE 42

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HONEY, I HURT THE FISH The 21 most common mistakes in fishkeeping – and how to avoid them.

FISHKEEPING ANSWERS PFK’s crack team of aquatics experts are on hand to answer all your questions. This month: keeping ricefish, nitrite testing, and how to tempt out a shy catfish, to name just a few.

KNOW-HOW: SETTING UP EXTERNAL FILTERS A step-by-step guide to setting

MONTH 107 NEXT Ram cichlids, Panaque catfish and Tiger barb alternatives.

114 TAILPIECE Nathan takes a friend to visit a public aquarium and comes out full of self loathing. Are these once-loved attractions now their own worst enemy?

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FASCINATING FISH Trochilocharax ornatus

R We still know very little about the mysterious Crystal rainbow tetra. What we do know is that it’s stunning as a stained glass window. WORDS: STEVE BAKER

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PRACTICAL FISHKEEPING

T. ornatus was first bought to the attention of ichthyologists when it was shipped from Peru in 2003 by German importers Aquarium Glaser. It was originally considered to be of the Heterocharax genus, before being described to science by Zarske in 2010. Zarske opened a new genus, Trichilocharax, and tribe, Trochilocharacini, for the Crystal rainbow tetra due to rather individual-looking dentition and some hooked fin rays that relate to no other characin – to this day we know of no closely related tetra. Other than just ‘Peru’, scientists aren’t sure about the distribution. The specimens used by Zarske to describe the species came from an imported group, and while they know the import came from Iquitos, they don’t know where the fish were caught, or from what kind of habitat. It’s widely believed T. ornatus hails from small blackwater streams with little flow, low conductivity and negligible hardness, and it does well

in these kind of conditions in aquaria. There’s some thought that their true distribution lies in the Rio Nanay basin, though preferred water conditions would be near identical to those mentioned. The new tribe is placed in the subfamily Stevardiinae, a group of over 300 species of Central and South American tetras with many members that adopt an internal insemination strategy. It’s believed that the Crystal rainbow tetra does that too. In the tank, this diminutive delicacy (1.7cm maximum) displays stunning colours under fullspectrum lighting, with blues and greens reflected in their bodies, and males displaying beautiful burnt oranges and yellows in their finnage. Sexes are easy to distinguish, with males harbouring longer, more colourful fins, especially the dorsal and pelvic fins, while females develop a slightly more rounded body.

Above: The subtle hues of Trochilocharax ornatus. WWW.PRACTICALFISHKEEPING.CO.UK

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NEIL HEPWORTH

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T’S OFTEN said that, as humans, we know more about space than we do about the oceans on the planet we inhabit. In reality that’s probably not strictly true; we don’t even know the size of the cosmos, let alone what might exist within it. But it continues to surprise me how little we know of what’s much closer to the surface, and this bonny little tetra is one creature we know of, but still know very little about. I look at this fish and think of a stained glass window, but in terms of a common name, Trochilocharax ornatus caught on as the Crystal rainbow tetra, Orange-tailed glass tetra, or the Hummingbird tetra, depending on who you talk to. Beware of researching by that last common name though, as Characidium fasciatum, the Darter tetra, is also sometimes called the Hummingbird tetra, and it’s a very different fish.

Latest news and events from the world of aquatics DISCOVERY

PREDATOR

FISH OF MANY COLOURS A stunning discovery.

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ESEARCHERS FROM the California Academy of Sciences, diving on the St Paul’s rocks, a deep-water reef 1,000 miles off the Atlantic coast of Brazil, have discovered a brilliantly coloured new species of Anthias. The divers were 130m down when the small fish caught their eye – its neon pink and yellow body and green fins made it stand out “like an emerald in a coal mine”. Further morphological investigation alongside DNA analysis confirmed the fish is indeed new to science, and has been named Tosanoides aphrodite in honour of the Greek

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PRACTICAL FISHKEEPING

DR LIUZ ROCHA “In a time of crisis for coral reefs, learning more about unexplored reef habitats is critical to our understanding of how to protect them.”

goddess of beauty and love. This is only the fourth Tosanoides species discovered, and the first to be found in the Atlantic (the others live in the Pacific). Females are a solid reddish-orange – typical of many ‘twilight zone’ dwelling fish as red and blue light can’t penetrate to this depth, so it helps with camouflage. However, the reason for the males’ ‘highlighter pen’ colouration is still being explored as it goes against this theory. The scientists are sequencing the fish’s vision genes to try to better understand the benefits of their extravagant colour scheme.

Scientists studying wildlife in Karnataka, South West India, have observed a praying mantis catching and eating fish for the first time. The famously predatory insect was already known to feast on other insects, small birds, amphibians, reptiles and mammals, but had never been seen to prey upon fish – until now. The team spotted the 5cm-long male, thought to be Hierodula tenuidentata, the giant Asian mantis, striding out among lily leaves in a roof garden pond and grabbing its guppy victims from just below the surface. It wasn’t a chance meal either, as the same mantis returned for several nights in a row to do a bit more fishing. As well as another reason for fish to be wary, it leads to further questions about the cognitive abilities of insects and the eyesight of mantises.

HENRY MARCUS, CREATIVE COMMONS

Scientists delighted but puzzled by new, strikingly coloured, ‘emerald in a coal mine’ Anthias.

SHUTTERSTOCK

WATCH OUT, THERE’S A MANTIS ABOUT!

© LUIZ ROCHA

NEWS

Aquatic News

WORLD’S MOST EXPENSIVE KOI SOLD

MYSTERY POLLUTION IN WALES An as-yet-unidentified pollutant has caused the deaths of thousands of fish in a 5.5-mile stretch of the River Clywedog, near Wrexham. Natural Resources Wales (NRW) has described the deaths as a “major pollution incident”. NRW will remain on site to monitor water conditions and assess the impact on wildlife and the environment, as well as investigating the source of the pollution.

A 90cm Kohaku called S Legend has sold for a record £1.4 million (203 million Yen) in Hiroshima, Japan. All we know of the buyer is that she’s called Miss Yingying and is from Taiwan, and intends to keep the Koi in Japan, where it’s expected to compete in shows.

SANCTUARY FOR PARISIAN GOLDFISH Upset by the poor conditions many goldfish are kept in, the Paris Aquarium is offering them a new home. Any fish handed in undergo a 40-day quarantine before being introduced to a large display aquarium that currently holds over 600 ‘rescued’ goldfish. It’s hoped that the facility will help to educate people about the adult size, lifespan and care needs of the humble goldfish.

NEW SPECIES OBITUARY

Trio of fragile Snailfish found

Jack Wattley, the ‘godfather of Discus’, has passed away, aged 95, on October 3rd, just seven days before his 96th birthday. An author, aquarist, businessman, competition judge and public speaker, Jack was recognised as a pioneer in the field of Discus breeding, producing some of the unique strains that are so popular today. Jack started out as a hobbyist – he was originally the owner of many clothes stores – until he began to venture to the Amazon. It was here that he sought out and found green Discus strains he’d heard lived in lakes in Brazil. After taking these home and succeeding with them, he returned to South America, this time in search of blue strains, which he also found, collected and shipped back home. By crossing the green and the blue, Jack created the first turquoise Discus to great acclaim within the industry. Demand – and Jack’s reputation – grew considerably. His fish acquired near-legendary status and he remains a household name in Discus circles. His other successes include the technique of raising Discus fry without parents, a method he kept secret for many years. Through this technique Jack went from being ‘just’ a breeder of high-quality fish to a successful producer on a commercial scale. Jack will also be remembered for the books ‘Discus for the Perfectionist’ and ‘Handbook of Discus’, which developed an almost cultish following. Some readers might also remember his contributions to the magazine world over his long career.

and fragile that they ‘melt’ if brought to the surface. This apparent weakness is actually a strength, as the immense crushing pressure at such depths would instantly kill more conventional fish. Growing 20-25cm in length they have temporarily been named the Purple, Pink and Blue Atacama snailfish, pending formal classification.

They are so soft-bodied and fragile that they ‘melt’ if brought to the surface

SHUTTERSTOCK

Snailfish look as ungainly as they sound.

ALAMY

An international team of researchers investigating one of the deepest parts of the Pacific Ocean has discovered three new species of abyssal fish. The team used remote underwater cameras to probe the Atacama Trench, which runs for over 3,000 miles at depths of over 8,000m along the coast of Peru and Chile. The new species are all from the Liparidae family, commonly known as Snailfish, and have made some startling adaptations to survive in this extreme, deep-water environment. They are scaleless, translucent, and their bodies are made of a gel-like substance, with the hardest parts being their teeth and the bones in the inner ear. Otherwise they are so soft-bodied

JACK WATTLEY DIES, AGED 95

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NEUROSCIENCE

ECSTATIC OCTOPUSES An octopus outside its usual rave habitat.

SHUTTERSTOCK

Neuroscientists researching similarities in animal brains have found that octopuses appear to react to the drug ecstasy in much the same way as humans, despite being separated by 500 million years of evolution. Octopuses are notoriously intolerant of their own kind, and are thought to be the most behaviourally advanced invertebrates. The research team first observed the interactions of octopuses for 30 minutes in a tank with three connecting chambers – one contained a plastic action figure, the other an octopus of the same species in a safety cage. They then exposed the same octopuses to MDMA (ecstasy) in a separate tank, before reintroducing them to the threechambered aquarium. After exposure to the drug they spent far more time in the chamber with the other octopus, and were far more tactile, hugging the cage and exposing parts of themselves

that they normally wouldn’t. The octopuses were also observed ‘fondling’ an airstone or floating around with all eight arms extended in what the team described as a ‘water ballet’. The brain chemical serotonin is believed to be fundamental in

these behaviours, just as it is in humans, and the team believes this study shows serotonin has an important role in social interactions right across species. This is not just a human or mammalian characteristic, but one of brains in general.

BEHAVIOUR

SHARK SHOWS SURPRISING TURN OF FIN Basking sharks, Cetorhinus maximus, are well known as the second-largest species of fish in the world, but few people had them down as fast swimmers – until now. When your major prey is plankton, speed isn’t really required, so the ocean giant is more typically associated with a laid-back, languid swimming style, with little more than the occasional tail fin flapping on the surface in terms of dynamic action. However, recent studies of the species have recorded them ‘breaching’ – hurling themselves right out of the water in a manner usually associated with faster-moving predatory species like the

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Great white shark. Once video footage of these leaps were studied in combination with data from tracker tags on the fish, surprised scientists worked out that some of these apparently sedentary sharks were reaching speeds of 11mph –

twice that of the average Olympic 50m swimmer. When the animal’s size and weight (8m long; 2,700kg) were taken into account, it was shown to be directly comparable to Great whites in terms of expended mechanical energy.

SHUTTERSTOCK

NEWS

Aquatic news

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SPECIES SHOWCASE Piranha

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The world can’t make its mind up about this South American shoaling predator. What’s the truth? Is it a cold-blooded predator or a much-misunderstood softy? WORDS: STEVE BAKER

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The fearsome teeth of a Red bellied piranha. WWW.PRACTICALFISHKEEPING.CO.UK 15

ALAMY

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SPECIES SHOWCASE Piranha

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ELL, IT’S a cold-blooded predator, literally. And it’s mostly misunderstood. But I don’t think I’ll go so far as to say it’s a softy. While the films ‘Piranha’ (1978), ‘Piranha 2’ (1981) and ‘Piranha 3D’ (2010) depicted our fishy friends as the most organised, hyper-aggressive killing machines freshwater has ever seen, now we’re bombarded by documentaries aiming to redress the balance. I’ve seen a presenter wade into a swimming pool with a shoal of piranha, and jumping into a river seconds after catching them to show they’re not just mindless killers. So should we ignore the films? Nothing to fear? At your

peril! The name ‘piranha’ means ‘tooth fish’ in the Brazilian language Tupi, and while few of us will come into contact with these feisty fish in the wild, if you do, approach with real care. There are many, many fishermen in South America with bits of fingers or toes missing, and even more with scars to prove these fish demand our respect. The largest species – the Black piranha, Serrasalmus rhombeus – has a bite force of more than 32kg. That’s from a fish whose record catch weight is 3.83kg, putting it ahead of the Great white shark in jaw strength comparative to body mass. Their teeth are made for cutting – each tooth is only about 4mm long, but they’re sharp as razors and fit snugly, interlocking to slice through flesh and steal a piece before moving on to let another fish take a bite. It’s not unusual to find piranhas with missing teeth. Several times over their life, they replace any missing tricuspid (threepointed) teeth, but rather than do it individually, like sharks, they do

MP&C PIEDNOIR, AQUAPRESS.COM

Red-bellied piranhas make three distinctive noises – a ‘bark’ at competitors, a low grunt when circling, and a snap of the teeth.

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it by quarters, growing and replacing all the teeth on one side of a jaw at a time. These replacements are ready developed in the jaw, waiting for when they’re needed. As with most opposing views, the truth about piranha behaviour lies somewhere in the middle. They are ferocious, voracious predators, who can strip all the flesh from a cow’s carcass in minutes, but at the same time, the diet of the Red-bellied piranha, Pygocentrus nattereri, is largely made up of aquatic invertebrates, crustaceans, insects, seeds, nuts and fruits. The classic Piranha ‘feeding frenzy’ comes down to feeding pressure. Through the best part of the year, Red-bellies swim in small shoals. Contrary to popular belief, they don’t shoal as an aggressive tactic to overcome prey, but rather for safety from the likes of giant river otters, caiman, river dolphins, eagles and predatory fish species. A shoal comprises around 20 individuals. Food is plentiful and aggression levels are low, so you

They don’t shoal as an aggressive tactic, but rather shoal for safety from the likes of giant river otters space to spread out, shoals BELOW: external filters rather than Piranhas are of piranhas meet shoals of one massive one; not only hundreds of other species, prey themselves. does this safeguard in case and where mass shoals of one filter fails, but two lots piranhas congregate, the of flow makes it easier to feeding pressure results avoid dead spots. in the annihilation of It’s ideal if heating is meaty passers-by, integrated with the dead or alive. filtration, either You’ll never by using in-line see this in heaters or a captive fish. For a thermofilter – this start, there just isn’t also provides peace same pressure to feed. of mind that there are no You’ll never have enough power cables in the water fish in a tank to create such to be chomped through. pressures without running into Lighting is up to the keeper. serious water quality issues, and if Although piranhas get stressed in a you limit food to heighten aggression, sparse tank, they aren’t upset by you’ll just end up with your piranhas strong lighting, so whether you want Captiothe n, tuckingcaption in to each other. dull illumination or a brightly lit caption, tank, your fish should be happy.

BELOW: A mature Black piranha showing red eyes.

won’t encounter frenzied feeding in these conditions. When water levels get lower, and large numbers of fish are brought together in everdecreasing streams and lakes towards the end of the dry season, feeding pressures are heightened. With less

Black background

Like other large fish, piranhas need clean, healthy water conditions, but produce a lot of waste to foul their tank. With no suitable tankmates to hoover up excess food, it’s a huge job for the aquarist, necessitating big, regular water changes and waste removal. It also puts the emphasis on providing strong filtration, both mechanically and biologically. Most keepers prefer to use two large

When attacking other fish, Piranhas first bite the fins and eyes to immobilise their prey before tucking in to more fleshy parts.

MP&C PIEDNOIR, AQUAPRESS.COM

LEFT: The revered Redbellied piranha.

Essentail maintenence ALAMY

At certain times of the year, Red-bellies congregate in large numbers.

When it comes to substrate, experienced keepers tend to go one of two ways – either a bare base or black sand/gravel. Bare glass is far easier to keep clean but the fishes’ colours tend to suffer. This can be limited by painting the base black (underneath) but the reflective glass is still likely to subdue colours slightly. A black substrate, be it sand or gravel, will help show off your fish, and can be further enhanced by strong, green plant growth. If you fancy a more subtle, atmospheric tank, go for a few large pieces of wood, sand, leaf litter and low light levels. A couple of spotlights to create shafts of light will intensify the mood. The next question is how many fish to keep. Red-bellies can either be kept singly or in groups of five or more. On their own, they are still active and show confidence and will need a minimum 200 l tank. The larger S. rhombeus is a solitary fish in the wild, but a solo specimen still requires a tank of 500 l, ideally 2m or more in length. In numbers, Red-bellies want about 100 l each, so a 150x60x60cm tank would be a basic set-up for a

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SPECIES SHOWCASE Piranha

small shoal of five, but you can really see the bonus of a larger tank with more fish. I’ve seen a few BIG piranha displays, 1,000-1,300 l sort of size and the result is stunning.

Distribution Red-bellied piranhas are widely distributed over much of South America. Since 1997, ichthyologists have classed Pygocentrus ternetzi (described by Steindachner 1908) as a southern strain of P. nattereri (Fink and Zelditch couldn’t find reliableenough characteristics to define a species), labelling P. ternetzi as a nonlinear cline (non-sequential features) as they differ in body shape and have more of a yellow belly than red. These fish often go under the trade name ‘Yellow emperor piranha’ in shops. P. nattereri are found throughout the Amazon basin including Brazil, Bolivia, Colombia, Ecuador and Peru. They’re also found in Rio Essequibo in Avoid the temptation to feed Guyana and ham, chicken, beef and so on. Venezuela, Rio The lipids from mammalian Paraná in Brazil, meats may not be Paraguay and metabolised Argentina, Rio Uruguay properly. in Brazil, Uruguay and Argentina, and among coastal drains in north-east Brazil and the Guianas. The Red-bellies don’t restrict themselves to particular habitat

Small shoals of Red-bellies are most natural. 18

PRACTICAL FISHKEEPING

Studies show that the sounds of people playing, washing and preparing food alert piranhas to a possible food source.

Red-bellies are found in major river channels, tributaries, and flood, oxbow and man-made dam lakes

Black piranha

RED-BELLIED PIRANHA 6Scientific name: Pygocentrus nattereri 6Pronunciation: Pie-go-sen-trus natt-er-air-eye 6Size: 35cm maximum, but rarely more than 25cm in aquaria 6Origin: Widespread through South America 6Tank size: 100x45x45cm+ for an individual 6Water requirements: 5.5-7.5 pH, 4-14°H 6Temperature: 24-28°C 6Feeding: Omnivorous – bloodworm, shrimps, earthworms, prawns, mussels, lancefish and fresh veg 6Availability and cost: Reasonably common; from £5

200 l+

FACTFILE BLACK PIRANHA 6Scientific name: Serrasalmus rhombeus 6Pronunciation: Serra-sal-mus rom-bee-us 6Size: 40-45cm 6Origin: Widespread over north and central South America 6Tank size: 200x50x50cm for an individual 6Water requirements: 5.0-7.5 pH, 2-15°H 6Temperature: 23-27°C 6Feeding: Mostly carnivorous – shrimps, lancefish, earthworms, prawns, mussels, etc. 6Availability and cost: Quite a rarity: from £50, depending on size

500 l+

Wild shoals protect the hierarchy. Older, bigger fish swim in the centre; smaller, BELOW: An immature young fish in formation Black piranha lacking colour around the edge. in the eyes.

SHUTTERSTOCK

types. They are found in major river channels, major and minor tributaries, temporary flood lakes, oxbow lakes and man-made dam lakes. They prefer deeper waters, but aren’t fussed whether they’re white, clear or blackwater conditions. Females generally grow larger than males and have a rounder body shape when mature, but the fish can’t be sexed as juveniles. This throws a fly in the ointment if you’re looking to keep a group, as males become territorial as they mature. A tank of mature males generally ends up with individual fish almost motionless in their part of the tank, and not the interactive shoal their keeper desires.

Evidence suggests that the Black piranha, Serrasalmus rhombeus, is endemic to Guyana. However, it’s officially been recorded as coming from Guyana, Venezuela, Suriname, French Guiana, Colombia, Ecuador, Peru, Bolivia and Brazil. It’s possible that sightings outside Guyana have been cases of mistaken identity as identification of certain species is challenging. Some expect S. hollandi and Pristoprycon aureus to be declared synonymous with S. rhombeus at some point. The red eye is a good identifying mark and gives rise to an alternative common name, the Redeye piranha, but the red eye isn’t developed in juveniles. Add to this the fact that geographical forms exist, there are several synonyms (such as S. niger), and confusion with common names ‘Black’, ‘white’ and ‘redeye’ all being used, and you can see the issues. Black Piranhas shoal in shallow, well-vegetated streams as youngsters, then become solitary as they age and mature, moving to deep areas of major rivers. Like the Red-belly, S. rhombeus adapts easily to different water types and is happy in steadily flowing water or at the edge of rapids – a favoured hunting ground. Food items include fish, crabs, insects, small mammals and chunks of flesh and fin bitten from big fish. Some keepers do mix them with other Piranhas, but there’s always a risk involved. Much safer to keep a lone fish and revel in that singular character. Despite their fearsome reputation, they can make a pretty good ‘pet’.

FACTFILE

MP&C PIEDNOIR, AQUAPRESS.COM

MP&C PIEDNOIR, AQUAPRESS.COM

NEIL HEPWORTH

P. nattereri with obvious red belly.

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OPINION

NATHAN HILL & STEVE BAKER We’re told it’s the most important aspect to fishkeeping and that we’re awful fishkeepers for not doing it, but just how essential is water testing for the modern aquarist?

hen was the last time you tested your water and found a problem? As a professional fishkeeper, how often would you say that you’ve been ‘saved’ by a test revealing something you wouldn’t otherwise have spotted? Is it possible for a fishkeeper to become so competent that they need not test water at all? SB: The last time I was saved by a surprise test result?... I don’t think I recall an occasion to be honest but, as a professional keeper, I’d say I’m pretty good at knowing what to expect, and my water testing is more to verify my thoughts or observe the maturing of a new set-up. The last time I tested water was a week ago, I wanted to check the GH and KH levels were stable and where I want them in a particular tank. I was also checking the performance of both a PO4 and an NO3 absorbing media. When I set up a tank, and as I’m adding fish, I’ll be testing between two and seven times a week, depending on importance. I do that until I think I know the tank, normally about three months, then I test bi-monthly, or if I see a change in the tank or the fish. To my mind, you can’t know what’s going on in your tank without testing. You can only assume, which is a risky game.

For argument’s sake, if I used RO water from a trusted source, and tailored it myself with minerals, I know the hardness of it, and I think I have enough hands-on experience to know exactly how the decoration I’m using (I’ll go wood and leaf litter) will affect the pH. I know I can add biological supplements and ammonia over such a prolonged period that maturation will be assured within four months – at least to a level that I could add half a dozen initial ‘hardy’ tetra to my tank. From there, it’s a patience game. If I leave it six weeks between additions, I have absolute confidence that the filter will have time to mature for each new load of fish. Let’s also assume I’m performing a weekly 50% water change, with enough mineral added to my RO to avoid any kind of mineraldeficiency filter-crash. Aside from power cuts or disasters outside my control, I can’t see that testing is going to tell me anything I don’t already know here. Thoughts?

JACQUES PORTAL

I’m sure I could wing it and get away with it, but I’d rather know what’s happening than risk the health of any fish

NH: OK, this will sound wholly arrogant, and it’s totally hypothetical, but I suspect I could set up a tank this minute and get it right through to completion – including with livestock – without having to test once.

SB: You can’t know, you can only make educated assumptions in that situation. I’m sure I could wing it myself and get away with it, but I’d rather know what’s happening than risk the health of any fish. Plus, you and I are experienced, professional fishkeepers. I guess you wouldn’t suggest this tactic for the average aquarist? When I worked in retail, I always found selling test kits tricky. They’re expensive and people think they are too sciency, too complicated and beyond them, but they’re the only way to know about the quality of the fishes’ environment, and far more important than substrate, lights, plants or ornaments. NH: From a personal perspective, any problems I’ve ever picked up from a test haven’t been during my regular, weekly

check-up. Problems are never that convenient as to happen on my test day. Rather, when I’ve spotted something – a fish looking a little off-colour – I’ve thought ‘that looks like a nitrite problem’, and tested it to confirm. My angle here is that I can’t recall a test catching an issue in an established tank before it became an issue. It’s always been the other way around. But I’d not suggest this to a newcomer. It’s only because I’m aware of how a sickly fish looks that I can second guess the problem and have it confirmed through a test. And my course of action is always the same anyway – water changes, ease back on feeding, and unburden the filter. Selling test kits is a nightmare. The thing is, for the best part they’re really easy to use. If you can fill a test tube to a line, add some drops from a dropper, shake and compare to a colour chart, then you can do it. But then, you don’t even need to do that any more. Something like a Seneye just goes in the tank and emails or texts you if the water quality shifts. How would you get people to test more often? Or test at all? How would you argue its importance, especially to the newcomer? SB: But the cost of a Seneye... for each tank! It’s not an option many will choose unless the price of such systems comes crashing down. As it is, it’s only likely to be bought by people who know the importance of testing water, and own a serious reef, Discus or similar tank. The strip tests came in to simplify things, but they’re still quite dear and mostly poor in their ability. To argue the importance, I would point out that testing is the only way to know exactly what’s in the water, and therefore what’s in your fishes’ blood. I would point out that coming to the shop for a water test is poor economy, as shops often charge for the test, plus there’s petrol money and the inconvenience to take into account. I would also point out that if someone sees a fish struggling on a Monday evening and can’t get to an aquatics shop until Saturday, there will be big issues before they know what’s going on. But then most people still

wouldn’t buy a kit, so I was obviously missing something in portraying how important I believe water testing to be. The fact that you “thought ‘that looks like a nitrite problem’, and tested it to confirm,” shows that it’s more important to have a kit at home, than to take a sample to a shop for analysis every fortnight. What’s your advice to novice and intermediate hobbyists in respect of testing? NH: I’ve tried a few approaches over the years, and I’d not say that any were entirely successful. I’m not even sure that the problem is expressing the importance of testing. Rather, I suspect the problem is that far too many people still look at fish as disposable commodities. For those people who care about fish, I’d say that testing (especially through an ongoing monitor like a Seneye) is a way to ensure they aren’t suffering, and a way to correct that suffering if it occurs. For those who don’t care about fish, I’d plug testing as a type of economic insurance. In a tank filled with £200 of livestock, a £30 bundle of cheap test kits annually is a way of protecting that investment. I’d back that up by explaining how the majority of problems in aquaria are due to water quality issues that can be resolved with regular testing. £30 is a night out with a couple of friends in a pub. I’m sure anyone can forego one of those a year. SB: I think you’re quite right there. Even a full-on liquid kit can be had for the equivalent of three nights out. But I think you’re probably sadly right that many casual fishkeepers see fish as disposable. They would rather risk the life of a fish, than splash out and learn to use test kits. As you say, it’s shortsighted – even with cheapish fish, a well-stocked 60cm tank may have up to £90 worth of stock. I think the myth of test kits being too sciency needs quashing too. Who can’t get 5ml of tank water, add three drops from bottle one, three drops from bottle two, shake and leave for five minutes before comparing the colours to a chart? if you need advice on the results, a call to your fish shop should see you right.

Do you have an opinion on water testing that you would like to share, or perhaps a topic you would like to see discussed? If so, you can find us at www.facebook.com/pfkmag or email [email protected]

INSET: The more water tests you can perform, the safer your fish will be.

INSPIRATION Stream tank

How flow can ALAMY

JAY WILLIS PHD Jay is a scientist researching hydrodynamics of river fish. He has worked on pigeons, beetles, tuna, whales and krill.

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set up a flowing stream tank, but how does a profess researcher go about it? d one, and this is what h

PRACTICAL FISHKEEPING

you go ? H

ILLSTREAM LOACHES are small freshwater species found in the fast-flowing streams of Asian tropical rainforests. In the wild, they glide over smooth rocks in strong currents and climb vertical, even overhanging surfaces with ease. Understanding how these tiny fish cope with such extreme environments might lead to significant breakthroughs in fluid dynamics, perhaps allowing us to reduce the drag on ships, or reduce the cost of pumping water. Hillstream loaches have unique scale structures and body shapes, and it may be these adaptations that give them the ability to fight the current without expending

significant amounts of energy. As researchers, our experiments are only worth doing if the fish we keep in the lab are healthy and behave as they do in the wild. We have spent several years improving our aquariums to match the ecotypes the hillstream loaches prefer. To that end we went to Borneo to see them in the wild.

Loaches in Borneo Hillstream loaches come from rainforest mountain streams. It rains a lot. Surprisingly there’s often only a thin layer of soil over bedrock or clay, so rain reaches the streams quickly. A river, normally a trickle, turns into a torrent in a few hours, or even minutes. Leaves, twigs, silt, gelatinous algae, and anything else that can’t get out of the way, is WWW.PRACTICALFISHKEEPING.CO.UK 23

INSPIRATION Stream tank

swept down on a torrent the colour of milky coffee. A couple of hours later, the clouds clear and the sun reappears; four or five hours later. the sediment drops out and the water clears. This cycle is repeated every couple of days to every few weeks, depending on the season. People in Borneo eat these fish, known as ‘rokot’, but it’s quite a trek to the high mountain streams, so they aren’t eaten often. Many people we met had fond memories of catching them as children and were keen to advise. One indicator was a certain aquatic snail: “Where there are snails there are rokot.” It was true and useful as the fish could be difficult to spot. We were looking at methods for sampling the fish in the future without harming them, so we captured a few with hand-nets and photographed them before returning them all to the rivers.

The tank To keep hillstream loaches happy, your tank should have some specific features: fast flowing water to allow algae to grow in strong lighting, darker protected areas with slower flow and even a few areas with little or no flow. Variation is the key. Like a tiny Adam Peaty, hillstream loaches probably need regular workouts to stay in top form, not

c th wa abo seco high like a compa moves about h per seco quickly d only a few from the p If you were a current of second throu 120 l tank, yo shift the entire second. That’s ome aquarium pump – 900,000 litres per hour! There is an easier way to get fast-flowing water though – keep some areas of the aquarium shallow. What we saw in Borneo has been applied to our tank design and husbandry. Water is pumped to a shallow platform, then flows over rocks and falls back into the main tank via a ramp or over a waterfall.

ALL PHOTOS|: JAY WILLIS

In the wild, when the stream floods, loaches climb, rather than shelter

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We used two Eheim compact+ 5000 pumps at full speed in a 100 l tank through sponges on strainers to move the water from the main tank to the platform. A rich layer of algae grows on the rocks in the strong light. The waterfall oxygenates the water and provides constant sound too; the ramp provides access and an interesting variable flow feature. We use ‘offline’ filters, and encourage shrimps, snails and algae to

ABOVE: We could learn a lot about hydrodynamics from hillstream loaches. BELOW: Sewellia ‘SW01’ and ‘SW02’.

share the tank. There’s no substrate, just large rocks and bogwood. The tank has both falling water and areas with moderate to low flow. In the wild, when the stream floods, loaches climb, rather than shelter. This time may be the equivalent of the Olympic final for these miniature Adam Peatys. The deeper water may allow them to get over objects that would be barriers in shallower water, and may also be where they can more easily evade predators like Clarias catfish. Catfish use suction to

RIGHT: This set-up offers different environments to replicate nature’s variety. BELOW: When flow drops, water settles and clears.

In their native Borneo, these loaches are called ‘Rokot’.

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catch prey and so the loaches’ ability to remain attached without substantial muscular effort may be a benefit in a surprise attack. This behaviour in stream flooding is subtly important as it means the filtering and nitrogen cycling services loaches aren’t challenging their physical limits all the time. Relaxation, that help ‘feed’ the main tank. The idea is that they act like an upstream rest and social activities are all parts of ensuring peak performance when section of natural river, adding smells and nutrition in the same way. necessary. Often, we found them in calm, clear pools, without excessive flow – 0.2-0.4 m/s. Here they would Water parameters The book ‘The Borneo Suckers’ by graze and share space with shrimps, Dr Tan Heok Hui provides other fish and snails; a good idea of what naturally inquisitive but hillstream loaches from always near shadows, Borneo are used to. and fast-flowing and From Dr Tan’s field falling water – ever Hillstream loaches often notes, the average vigilant. Our tanks remain stuck to rocks and pH of the water is are designed to other decoration even 7.5, with records mimic these variable after they’ve died! from 6.0 to 8.7. conditions in shelter, There’s no similar book lighting and flow. for the Sewellia butterfly We also use ‘offline’ living loaches of Vietnam, but there is a filters – tanks connected to the great scientific paper for main tank via smaller pumps. The Sinogastromyzon puliensis, a similar return water is piped onto the upper species found only in Taiwan. platform of the main tanks, often Shyi-Liang Yu and Teh-Wang Lee through a spray bar, to add to the sampled fish in over 60 river sites. flow. These smaller tanks contain Average pH was 8.2 (range 6.2-10.9), filter sponges, Anubias, shrimp, average temperature 23°C (range snails and fish such as Danios. We 18-30°C), average flow 0.9 m/s also put peat, Catappa leaves, Alder (range 0.12-2.32). These average cones and bogwood in here. We parameters are a good place to start. feed the Danios flake and some We always aim for them – also with circulates through the main tank. carbonate hardness over 7° kH, These tanks provide a range of

Where there are snails, there are rokot

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which pulls the pH up to roughly 8.0. As a rule, we don’t measure pH or GH, but monitor and maintain KH around 8-10 units. We tested the water in Borneo with standard test kits (API liquid test kit KH, GH, and pH) and confirmed these average figures were accurate for five of the locations where we found fish.

Feeding While hillstream loaches will eat standard fish flakes, we’ve found

ABOVE & BELOW: Flow rates fluctuate massively in the forest streams of Borneo.

Not just algae, hillstream loaches need the right algae.

they need to eat algae for long-term health. We use Repashy Soilent Green gel as a supplement to ensure they always have access to a well-balanced diet. There are many types of algae, of course, and some only grow in fast flow. After rocks have been grazed by adult hillstream loaches for a few months, they develop a dark, redblack algal layer full of bacteria, crustaceans, diatoms, and other food, such as snail and shrimp eggs. Gelatinous algae can be a sign that there’s too little flow in the tank. It’s not toxic to the fish, it just stops them getting at the stuff they like.

Husbandry

explore and re-establish favourite places and routes. We often find small fry in the changed water and move these to a separate tank for juveniles. Occasionally we roughly scrape the rocks with an old knife – the fish seem especially keen to graze them after. The behaviour we observe in our aquariums is similar to what we saw in the wild. Like many loaches, hillstreams like to hide, especially from people, and we ensure they have adequate places to do so.

They’re naturally inquisitive and social fish; while they may hide when we enter the room, they re-emerge after only a few minutes. All sizes playfully spar with similar-sized fish and they appear MORE INFO relaxed as they explore Check out Jay and his their tank. colleagues’ informal project One good test of blog: aquaticagents.com. health is breeding and Scientific project funded by we’re pleased to say The Leverhulme Trust. some of our fish more or less breed continually. Repashy’s algae paste food goes down well.

Because these fish are used to change in their natural rivers, they don’t mind a big water disruption. We clean the tanks weekly by removing all the rocks and wood – everything out but the fish! So all the rocks in the main tank are rinsed in tank water and repositioned, with a 40-50% water change. The changing pattern of rocks and caves, in a familiar pattern of flow, is a further stimulant to the fish, similar to their natural habitat, and allows them to WWW.PRACTICALFISHKEEPING.CO.UK 27

BIOLOGY Ambush predators

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CHRIS SERGEANT Chris works in conservation research and regularly writes for aquarium publications.

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It’s all part of the food chain.

PRACTICAL FISHKEEPING

THE ART OF THE

AMBUSH Fascinating to observe, ambush predators of all shapes and sizes have devised an arsenal of strategies to capture their prey.

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S

much of the attention, the attached videos of the octopus hunting shrimp also caught the eye.

Surprise, surprise While the Larger Pacific striped octopus’s particular method might be a first, the art of ambushing prey – defined as a ‘surprise attack from a concealed position’ – is nothing new, and a ploy utilised throughout the aquatic animal kingdom. Such predators typically hunt much faster prey items, and would be easily outpaced in a straight race, so they use camouflage, mimicry or the local topography in order to conceal their whereabouts. Coral reefs and the surrounding sandflats play home to some of the ocean’s most cryptic ambush hunters. Stonefish, Synanceia verrucosa, lie among the coral, perfectly disguised against the rockwork, while species such as Papilloculiceps longiceps, the Tentacled flathead or Crocodilefish, make use of rocky ledges and the

RIGHT: Crocodilefish even have camouflaged pupils. BELOW: Stonefish mimic algae-covered rocks while lying in wait.

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TEALTHILY APPROACHING a shrimp, the octopus pauses a short distance away, seemingly poised to strike. But instead of accelerating at speed, the crafty cephalopod slowly unfurls a tentacle, reaches round to the back of the shrimp and gently taps it on the abdomen. Startled, the shrimp jolts forward in surprise, straight into the waiting open arms of the octopus. Videos of this canny hunting behaviour captured the attention of fish-lovers and academics alike in 2015, when Roy Caldwell and Richard Ross from the California Academy of Sciences published a paper in the journal ‘PLOS One’. Their study looked at the biology and behaviour of the little-known Larger Pacific striped octopus, based on observations of their captive specimens. While the cephalopod’s unique beak-to-beak mating strategies and den sharing grabbed

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surrounding sand bed. Crocodilefish have flattened, elongated bodies that give rise to an almost ‘steamrollered’ appearance. Added to their adjustable mottled brown and tan colouration, they blend seamlessly with their surroundings. Various tassels and protrusions help to break up their outline, and their camouflage is so detailed that even the pupil is covered with an iris lappet, disguising the outline of the eye. Other species, such as the Atlantic lizardfish, Synodus saurus, or Peacock flounder, Bothus mancus, choose to rest on the surface of the substrate, while reef predators like the Red grouper, Epinephelus morio, and Trumpetfish, Fistularia commersonii, drift slowly around their hunting grounds until their prey become accustomed to their presence. Once a false sense of security has set in, they’re able to ambush their targets with ease. Thankfully, you’ll be hard pushed to find these species with their voracious, indiscriminate feeding habits and large size in the hobby, but certain other predatory reef hunters are better suited to life in a home aquarium.

an eye. With this expandable mouth, pharyngeal teeth and a stomach that can swell to 30 times its resting capacity, lionfish can comfortably consume prey half their size. The Common lionfish, Pterois miles, and Red lionfish, Pterois volitans, regularly appear in the trade, but can attain adult sizes in excess of 38cm, so they need a tank to match. The Spotfin lionfish, Pterois antennata, reaches half that size, about 20cm, while smaller still, the Fuzzy dwarf lionfish, Dendrochirus brachypterus, can be kept in tanks of 150 l.

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Masters of disguise

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Lionfish are eye-catching, sporting vivid splashes of red, white and black across their outstretched body and fins. While most ambush hunters rely on remaining hidden, the lions’ striking appearance seems at odds with this tactic – against the backdrop of a well-lit aquarium, the aposematic colouration boldly publicises the fish’s venomous nature to the world. But when the light drops, the true cryptic effect of these colours is

revealed. The red, white and black stripes, so conspicuous by day, merge into the murky backdrop of reef and rock, breaking up the fish’s outline as it lurks in the shadows, camouflaged from possible prey. With all lionfish, any tankmate that can fit inside their mouths inevitably will. Like their other Scorpaenidae cousins, they feed by rapidly expanding their buccal cavity, which generates a suction field and allows them to inhale prey in the blink of

BELOW LEFT: Hawkfish use a perching strategy to look over their prey. BELOW: Flamboyant camouflage works on the reef.

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Lion king

For those wanting something a little more unusual, look no further than the Weedy scorpionfish, Rhinopias frondosa (see PFK, July 2018). In contrast to the more active, larger lionfish, it lacks a swim bladder, so prefers to hop over the sand using modified pectoral and pelvic fins. Being a relatively sedentary hunter, camouflage is critical, so what better way to blend in than to mimic your environment – specifically the local macro-algae, which gives the fish a spectacularly plumed appearance. Hawkfish are another group of ambush hunters that rest on coral or rocky perches, motionlessly surveying the reef. When a prey item comes into reach, they swoop down from their vantage point and snatch up their victim before returning to their perch, much like their avian namesakes. Their inquisitive nature and dinky size make them a favourite among

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marine aquarists, so several species feature in the hobby. The Falco hawkfish, Cirrhitichthys falco, Pixy hawkfish, C. oxycephalus, Threadfin hawkfish, C. aprinus, and Longnose hawkfish, Oxycirrhites typus, all remain under 13cm when fully grown. Ribbon eels, Rhinomuraena quaesita, also crop up in the trade from time to time. Spending their time hidden in the rockwork with only their heads exposed, they dart from the security of their lair to snatch fish or crustaceans from the water column. Unfortunately, ribbon eels are renowned for their refusal to eat anything but live foods in captivity, and their pristine water requirements don’t tally with a meat-based diet. Beautiful as they are, they are best left in the wild.

Shrimp strategy Fish aren’t the only creatures to use ambush strategies. Many invertebrates also lie in wait to bag themselves a meal. Mantis shrimps

from the order Stomatopoda live in rockwork or burrows dug into the substrate. Obscured from view in their tunnel, they wait until a potential target passes overhead before launching themselves at speed. Unlike true shrimps, Stomatopods possess pairs of raptorial appendages, with ‘smashers’ such as the Peacock mantis shrimp, Odontodactylys scyllarus, using a punching technique to overcome their prey, and ‘spearers’ like the Zebra mantis, Lysiosquillina maculata, impaling their quarry on their outwards-facing spines. At over 50mph, a punch from a Peacock mantis shrimp can deliver an impact similar to a small calibre bullet. As the mantis shrimp swings forwards to strike, the movement lowers the pressure of the surrounding water, causing it to boil. This instant forming and collapsing of bubbles produces energy through cavitation, giving a second blow to the victim. Even if the initial strike

narrowly misses, the resulting shockwave will finish the job. When housing mantis shrimps When housing from the order Stomatopoda, stomatopods, tank decor is important. Both low lighting is a must, as species dig burrows, so strong illumination can you need either a deep lead to shell rot. sand bed with coarse sand and coral rubble, or a network of dark PVC tubes buried beneath the substrate. Live rock will help disguise the pipes and serve as extra cover. The more hiding places, the safer the shrimp will feel, and the more frequently you’ll see it. While mantis species can enter aquariums as live rock stowaways, their unintended presence doesn’t strike fear into a reef enthusiast the way mere mention of the Bobbit worm can. Marine aquarists may already be familiar with Eunice Fleshy aphroditois’ capabilities, but it extensions and was Sir David Attenborough who ragged-looking introduced this polychaete worm fins break up a to the rest of the world in ‘Blue fish’s outline.

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Ambush predators

Ribbon eels prefer to conceal.

Planet II’, plucking fish after fish from the water column. Buried in the sand, with just their jaws exposed, Bobbit worms make quick work of any prey, snaring them in their razor-sharp teeth before dragging them deep into their burrow. Hidden in the rockwork of your reef tank, they will make short work of your marine fish, and often the entire reef set-up has to be dismantled to get rid of the worm. This is one ambush predator you don’t want to encounter!

Spending their time hidden in the rockwork with only their heads exposed, they dart from the security of their lair to snatch fish or crustaceans from the water column adopt a similar tactic in the murk waters of the Congo River, seekin shelter at the edges of raging rap As the torrents of water cascade overhead, disorientated fish swept around in the currents are snatched up from the margins. While it shares its locality with the Tigerfish, the Leopard bushfish, Ctenopoma acutirostre, prefers a much quieter pace of life. Seeking submerged driftwoo

The Zebra mantis shrimp spears its prey.

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The Peacock mantis shrimp is a hard hitter.

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Rather than camouflage, many freshwater ambush predators rely instead on the underwater topography. Hidden within a shaded lookout – overhanging vegetation, sunken obstructions, or even manmade structures like jetties – the sensitivity of the fish’s eye increases in low-light conditions, giving it a greater field of visibility in comparison to a fish in open water. This allows the predator to spot its quarry first, and when fractions of a second can make the difference between a meal or a missed opportunity, such advantages can be crucial. The Northern pike, Esox lucius, is the UK’s apex freshwater predator and ambush hunter. Skirting round the edges of large lakes and ponds, Pike hang motionless in thick vegetation, emerging with short bursts of speed to grab passing fish or water fowl. Goliath tigerfish, Hydrocynus goliath,

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Shadowy affair

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and dense foliage for cover, it adopts a head-down hunting stance, mimicking leaf debris, while its spotted kittenish colouration helps to break up its outline. Adults can reach 20cm and their deceptively large, extendable mouths make them capable of taking any sizeable prey that strays within reach.

Leafy disguise Hop across the Atlantic to the slow-moving water bodies of the Amazon River basin, and there’s another aquarium species whose disguise has been inspired by decaying leaf matter. The Leaf fish, Monocirrhus polyacanthus, has seriously upped the mimicry stakes. As well as a leaf-shaped body, mottled-brown colouration, and head-down swimming stance, the shape of its eye – the main giveaway with many cryptic ambush predators – is broken up with bands of colour, while a projection on the lower jaw

ABOVE: Bobbit worms are the stuff of nightmares. BELOW: Pike lurk by shady features to get a sight advantage.

gives the impression of a leaf stalk. Coupled with a tendency to drift rather than swim, and the ability to adjust its colouration to match the surrounding foliage, this puts the Leaf fish among nature’s finest mimics. With their extendable mouths, they can take prey items up to 30% of their body length. The speed of M. polyacanthus’ strike has been measured at 0.034 seconds from the initiation of the strike to prey capture. Incredibly, another species in the marine trade, the Bluestripe pipefish, Doryrhamphus excisus, was even faster with a strike-capture speed of 0.002 seconds. Despite their lightning-quick reactions, Leaf fish can be finicky eaters in captivity, so are suitable for experienced aquarists only. Gut-loaded live prey is a must while trying to shift them onto frozen or prepared foods. They require a low flow set-up, low pH and hardness to mimic natural water parameters,

and won’t tolerate fluctuating ammonia and nitrites.

Leaves as camouflage Hailing from the blackwaters of South-East Asia, the Pikehead, Luciocephalus pulcher (see PFK, September 2018), makes use of fallen branches and leaf litter from above. The tannin-stained waters provide the cover from which it darts out to grab its prey, with its protrusible jaws capable of extending almost a third of its body length – impressive given that adults can reach 20cm. These predators aren’t for the novice aquarist though, and not just because they prefer live, rather than pre-prepared diets. Coming from such acidic waters, where there is little in the way of local bacterial communities, they can be susceptible to infections. The Wolf-fish, Hoplias malabaricus, is a predatory characin that also goes by the names Trahira or Guabine, depending on their Central or South America source. Their nocturnal

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Going underground Other ambush predators prefer to go fully subterranean in their hunting efforts. Endemic to São Francisco River basin in n th-east Brazil, the Pacman catfi Lophiosilurus alexandri because its vast mouth was likened to the 1980s arcad game character. I grows up to 50c length and spend majority of time buried the sand with just its head

ABOVE: The Bluestripe pipefish strikes in 0.002 seconds.

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anything that swims by. Certain Pufferfish also engage in burying behaviour. The Hairy puffer, Tetraodon baileyi, and Pignose puffer, Tetraodon suvattii, from the Mekong basin, appreciate a fine, deep, sand substrate, interspersed with rocks, as do the African Congo puffer, Tetraodon miurus, and Fahaka puffer, Tetraodon lineatus. Pufferfish have personality, but a general intolerance of conspecifics, and predatory behaviour towards tankmates means they’re best suited to solo

BOTTOM: The Leaf fish is a top mimic. INSET: Lurking Puffers bury most of their bodies.

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their cavernous mou rows of small teeth to grip their inhaled prey. Larger prey items are dragged back to their shelter and devoured at leisure. Unsurprisingly, these large catfish require equally large aquariums, with sunken wood, rocks and caves for shelter. To improve your chances of observing them in a tank, try to position cave entrances so the occupant faces outwards.

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feeding habits mean they spend most of the day hidden among the vegetation, before emerging at night to hunt. Having said that, any fish that strays into range during daylight hours is still likely to snared in their vice-like grab – their canine teeth and reluctance to let go of their prey giving rise to the wolf comparison. Popular in the trade, adults can reach 40cm, so real consideration needs to be given to housing them. Another group of benthic ambush hunters from the Amazonian region are Cephalosilurus. These catfish have large heads and small eyes, which add to their already bulky appearance. Four species are currently recognised, with C. apurensis from Venezuela, and C. nigricaudus from Surinam, being the two most often encountered. Cephalosilurus live life in the slow lane. They stay motionless in a favourite hiding place, snatching anything that swims by. Barbels around the mouth enable them to detect movement in the water, and

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BIOLOGY Ambush predators

living. As with all Puffers, crunchy prey items, such as unshelled shrimps and snails, should be fed regularly to wear down their teeth and prevent overgrowth. For those with truly mammoth aquariums, another burrower, the Ocellate river ray, Potamotrygon motoro, has a particularly novel approach to feeding. While it was once thought only mammals chew their food, these rays have been observed grasping their invertebrate prey in one corner of the mouth and moving the sections of their jaw from side to side, creating a shearing effect. Even if tough exoskeletons are capable of withstanding the crushing power, they’re no match for this tearing action.

Come into my parlour Patience is key for all ambush hunters, but some species have specialised adaptions to entice prey during lean spells. Bioluminescence is commonplace in the deep ocean, and an ideal way to get the attention of passing prey. Some siphonophores, Erenna sp., use flashing red tentacles to mimic swimming copepods, the first recorded example of a marine invertebrate using red bioluminescence to tempt in victims. Numerous deep sea fish use the same tactic – Barbeled dragonfish, Chauliodus sp., use an elongated barbel protruding from their lower jaw, while Atlantic footballfish,

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PRACTICAL FISHKEEPING

Himantolophus groenlandicus, have a modified ray tipped with a luminous bulb that they flick about to attract prey in the abyss. In shallower waters, reef residents also use lures to grab their victim’s attention. The Decoy scorpionfish, Iracundus signifer, is native to the Indo-West Pacific and its mottled red and white colouration helps to break up its body outline against the reef backdrop. A closer look at its spiny dorsal fin reveals a prominent black spot between the first and third fin rays which, when viewed from the side in conjunction with the other spines, mimics the head of a small fish. This aggressive form of mimicry lures would-be predators, who in a flash find themselves inhaled. Rather than employing a static lure, the benthic-dwelling Angler

flatfish, Asterorhombus fijiensis, has an elongated first dorsal fin ray tipped with a membranous structure. By remaining stationary and flicking the fin ray above its mouth, these flatfish can mimic tiny hippolytid shrimps and bring food right to their mouth.

Fishing frogs Another group of reef fish can be observed casting their lures in the aquarium. Frogfish are members of the Antennariidae family, and their lack of a swim bladder means they crawl, rather than swim, over the reef. Their impeccable camouflage mimics a variety of different reef species, such as sea urchins, sponges, tunicates and coral. Assorted warts, fleshy protrusions and coloured patches allow these predators to blend in with their environment, and

ABOVE: The Barbeled dragonfish lures prey with an elongated barbel. BELOW: The Goliath tiger fish picks off disorientated prey from rapids.

they can even alter their colouration over the course of a week if it’s not up to scratch. The Frogfish waits in its ambush site for a potential meal to approach, and when one gets close, the show begins. The fish’s modified dorsal ray, or illicium, is tipped with a lure, or esca, which acts like a fishing rod to reel in any interested parties. As the prey gets closer, the frogfish keeps its body compressed to the ground, and orientates its mouth upwards in the direction of its quarry. As soon as it gets within one body length away – the ‘strike zone’ – the Frogfish pounces. By forcing its upper jaw out and lower jaw down, it can expand its cavernous mouth 12 times its resting state. This creates a negative suction pressure within its mouth, sucking in its prey in a blink of an eye. Such is the speed of the strike, a mere 1/6000 of a second, that a Frogfish can

pluck a fish from a shoal without the others realising what has happened. The Frogfish’s hunting strategy is so sophisticated that its esca comes in different shapes and sizes depending on the species it’s mimicking. The Giant frogfish, Antennarius commerson, and Warty frogfish, Antennarius maculatus, use lures resembling shrimp; Randall’s frogfish, Antennarius randalli, mimics a juvenile squid; while the Threespot frogfish, Lophiocharon trisignatus, resembles a spidercrab. Different Frogfish even have distinctive casts – the Giant frogfish fishes above its head in the water column, while the Warty frogfish waves its lure in a circular motion in front of its mouth. Another species, the Striped frogfish, Antennarius striatus, even secretes a chemical attractant from its esca to help it hunt in particularly turbid waters.

From a freshwater perspective, the Frogmouth catfish, Chaca chaca, also uses lures to attract prey, manipulating the barbels on its mouth to resemble worms wriggling on the substrate. If keeping Chaca species in an aquarium, be aware that they seem to reduce the pH of their aquariums. It’s not yet known how this occurs, but theories include the release of a chemical lure to entice prey, extremely potent digestive juices, or a foul-tasting secretion to prevent predation. Whatever the reason, regular water changes and testing is a must with these fish. So, if you are considering housing one of these incredible predators, be sure to have your tank decor and layout in check. The more cover you provide, the more likely your aquarium inhabitants are to engage in their natural ambush behaviours. That leaves you to just draw up a chair and watch nature in action.

BELOW: The Atlantic footballfish is a deep water fisherman.

Atlantic footballfish, Himantolophus groenlandicus, have a modified ray tipped with a luminous bulb that they flick about to attract prey in the abyss

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COMMON SPECIES SUBJECT TO INJECTION AND DIPPING

MP&C PIEDNOIR AQUAPRESS

6 Albino corydoras 6 Glass fish, Parambassis sp. 6 Parrot cichlids 6 Black widow tetra 6 Giant gourami

WHAT’S WRONG WITH INJECTED FISH? Fish can be artificially coloured in a couple of ways – Fish have their mucous layers stripped, before dunking in concentrated dyes stains them with artificially bright colours. 6 Fish are dyed all over including the gills, causing respiration issues. 6 Ink in the body can have serious effects on organ function. 6 Stripping away mucus leaves fish open to bacteria and parasites. Fish are stabbed with a needle, and dyes injected. They may have patterns or words tattooed on the body. 6 Against fish body sizes, needles are huge. Imagine your armbeing injected with a pencil for a comparison. 6 Injection sites are access points for infections. 6 Needles are not cleaned or sterilised, risking infection. 6 Chemical embolisms from injection can cause fatalities. 6 Injecting causes granulomas, tumours and cauliflower like growths. 6 The dyes cause inflammation of skin and muscle tissues. 6 Injecting requires rough handing which is highly stressful.

or

Are they legal? It IS illegal to dye a fish through dipping or injection in the UK, but NOT illegal to import or sell them. Almost all dyed fish are commercially produced in the far east, and imported directly.

What can you do? Ask if retailers have joined up to the Practical Fishkeeping Dyed Fish Campaign. Started in 1996, the campaign asks retailers to pledge not to sell any dyed fish. If you see some on sale, raise your concerns with store owners. Because dyed fish aren’t always advertised as such, staff may genuinely not know they are stocking them! Your voice can help make the difference!

FISHSCIENCE AQUARIUM FOOD The writer of our Letter of the month will win a 250ml pot of their choice from this quality range of Fish Science food, which uses natural ingredients. Email: [email protected]

TANK COMMUNITY

Letters

Win

Your letters, your thoughts and your experiences shared. still have very similar patterns on their bodies to the farmed wild varieties of angels. Or perhaps using hybrid fish like the electric blue versions of the Jack Dempsey or Mikrogeophagus ramirezi or even the hybrid Electric blue acara in Central American or South American biotope/habitat/ communitope set-ups. This is my personal experience anyway, and I hope it might give a bit of thought to those of us who – like me – sometimes intentionally or unintentionally go into a moment of biotope snobbery that might prevent others from delving into this fascinating portion of the aquarium hobby. Andy Basuki, Indonesia NATHAN REPLIES: I like to think that Tai did spark some discussions with his comments – he certainly did right here between the PFK staff! I’m an unashamed biotope snob, and while I appreciate it’s a niche of a niche of a niche, I can’t think of any better way to really enjoy the wilderness aspect of fishkeeping. Admittedly, I’ve played with plenty of communitopes, and more than a few communities, but my heart always goes back to the absolute, purist layout. Perhaps there’s something about the untamed, unrestrained and artistically chaotic nature of nature,

NEIL HEPWORTH

I was re-reading the March 2018 of Practical Fishkeeping and stumbled upon Tai Strietman’s Thai tank set-up. I find that creating and recreating biotopes is a lot of fun, as shown by my earlier letter to PFK in regards to Nathan Hill’s Neon tetra biotope set-up. As you might remember, I talked about the natural behaviour of my Sawbwa resplendens in my Lake Inle tank set-up (which is sadly no longer active as it faced a tank crash when I was away, and a power failure wiped out the fish population – a sad loss of such beautiful fish). I am slowly spreading the love of biotope tanks in the country I am from and, regarding the biotope snobbery that Tai mentioned in his article, whether intentional or not, on reflection I may have done so to my dismay. I know that it is a sad thing, but I have since then done some reflection and tried to guide people in trying their best to create a habitat or biotope with substitute fish that might look similar to the fish that may be available in the biotope they are creating, or even the plants. I sometimes even helped them in finding out what possible fish those might be in the area of biotope/ habitat that they are creating for a communitope kind of set-up if a true biotope/habitat is not possible. The only time that I might dissuade people from putting in certain fish is when they use the ornamental versions of angelfish in an angelfish habitat set-up, though I do encourage them to try to find the farmed, wild forms of angels that are now starting to be more available in the hobby. Alternatively, I might suggest they use those ornamental forms that

but show me a pristine planted aquascape, and a mud-filled, algae-drenched slice of Amazon oxbow, and I’ll make a beeline for the tank full of muck every time.

WHERE ARE THE LOCAL FISH SHOPS GOING? I used to have three independently owned LFS that I could visit, but now there’s only one pet store with some fish, or a long journey to visit an out-of-town shop that has a reasonable selection of fish. Where I live isn’t lacking fishkeepers. There are plenty of us here, and these stores were all rather well established. Is there a reason that stores are closing down like this? I hear the same thing when I speak to fishkeepers in other counties too. B Heldon, email

ABOVE: Electric blue Jack Dempsey. BELOW: Asian rummynose, Sawbwa resplendens.

NATHAN HILL

HUMBLE ABOUT BIOTOPES

NATHAN REPLIES: It’s a tough time for all stores, not just independent ones. I’m seeing lots of shops vanishing, and it doesn’t look like a trend that’ll go away any time soon.

❯

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I guess someone just needs to work out what the next evolutionary stage of aquatic trading should be, and hopefully we’ll see another golden age of fishkeeping. High rents and business rates, high transport costs, high fuel costs, and the difficulty of trying to hire staff with expertise (there really are only so many, and most of them are already in the industry) make it a hostile environment in which to run a shop.

DO AQUASCAPERS REALLY NEED FILTERS? I’m hoping you can answer something that’s been on my mind. We all know that plants eat up fish waste, and that planted aquascapes have a huge amount of planting compared to the number of fish in them. So does that mean I can run a tank without a filter? And if not, just how much planting would I need to stop needing a filter? Gary Sneddon, email NATHAN REPLIES: I’ve had a situation where I accidentally left a filter off over a whole weekend in a planted ‘scape, and only noticed when I spotted there was less flow and a little more debris on the base than usual. Obviously, I panicked and tested the water straightaway – only to find zero ammonia or nitrite. That was in a 99 l tank with a LOT

of Cryptocoryne and about 20 smallish rasbora (3cm or so). My tank coped admirably. So yeah, I guess in theory you can do it. Plants uptake ammonium directly as a food source (they actually have to convert nitrates back into ammonium in order to utilise it), so as long as they’re established and there’s ample flow and circulation in the tank, then it should work. I’ll still always run a filter ‘just in case’ though.

IN PRAISE OF LIVE FOOD I wanted to thank you, and especially Gabor Horvath, for your recent feature on breeding live foods. I’m a bit of a hoarder and I’m unable to throw out my old, scratched tanks – they’ve been clogging up my shed and parts of the garden for years. After reading Gabor’s piece, I cleaned up two of them to put in a sunny spot in the garden, and bought myself a couple of bags of Daphnia and Cyclops to grow in them. After a slow start where nothing happened for the first week, they had a bloom of life and now I have more than enough wriggling things to treat my fish to a daily live feed. They love it! I’m now awaiting a delivery of microworms I bought online, and have my porridge oats at the ready!

ABOVE: Gabor’s simple infusoria set-up.

PRACTICAL FISHKEEPING

With all the live food they’re now getting, I don’t think it will be long before my Kribensis start to spawn, so I want to be ready for it! R Marsh, email

GLASSY EYED I was fascinated by Tai Strietman’s glassfish tank in the October issue of PFK and have now decided I want to set one up for myself. My only question is, where can I get quality glassfish from? I don’t feel brave enough ordering online, knowing that there are so many injected ones out there, and my local stores all seem to have quite tatty fish. I’m based not far from Derby. Jenny Sands, email

LEFT: Aquascapes – the ultimate veg filter.

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GABOR HORVATH

TANK COMMUNITY

Letters

Email us at editorial@ practicalfishkeeping.co.uk

NATHAN REPLIES: I think Tai’s fish came from a Maidenhead Aquatics, and I believe there’s a Derby branch worth a visit. If you get no joy there, give Wharf Aquatics at Pinxton a try. Phone up in advance and if they haven’t got any, I bet the guys there will happily order some in for you.

Write to us at Practical Fishkeeping, Bauer Media, Media House, Lynchwood Business Park, Peterborough, Cambridgeshire PE2 6EA

THE VOICE OF YOUTH I was reading the November issue of Practical Fishkeeping and I found the opinion piece on young people in (or rather, not in) the fishkeeping hobby very interesting. I’m a 20-year-old living in Ireland and while I’m fairly new to this hobby, I like to think I still qualify as ‘young blood’, so I thought I might give my own take on the topic. The article touched briefly on what I think is the key issue – cost. Fishkeeping is a hobby that, particularly when starting out, requires a great deal of investment, not only in money, but also in time. I must have spent hours on end researching before I even bought a single thing. The set-up itself has cost me the equivalent of two or three smartphones. However I consider myself very

privileged to be able to take on that cost. I work part time, along with university, but I’m also able to live in my family home, so I pay very little in rent or utilities. Many students are renting or living in on-campus accommodation, many of which don’t allow fish tanks due to the risk of water damage. Even if they did, many students then return home for the summer and transporting a fish tank of any size is something of an ordeal. For younger children and teenagers still in primary or secondary education, the barrier is still monetary cost for many. They don’t have jobs, so their parents must foot the bill, and attempting to convince most parents that you need to spend more than £50 on a fish is a task in and of itself. Not to mention that many of us have had fish in the past – a goldfish perhaps, in a 10-litre bowl. It died

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after a week or six months or a year, and we convinced ourselves that we must be fish murderers, and shouldn’t put any more living creatures in such perilous hands ever again. This was my experience, until I tentatively began to look back into the hobby again. The typical childhood experience of fishkeeping, except for those with parents in the know, is often lacklustre. That said, I know quite a few people my age who would certainly be interested in the hobby – just not right now. Much like having any pet, many of us simply have to wait until circumstances become favourable. I certainly plan on upgrading once I’m older – once I have a house, and a career to pay for it. Who knows when that will be, but I’m hopeful it could happen some day. Alex Twyford, email

Tai is clearly an inspiration to fish keepers.

STARTING WITH CLUE 5 GUESS THE FISH USING AS FEW CLUES AS POSSIBLE

5

This fish is probably the best known of all the species highlighted by the Big Fish Campaign, which seeks to stop their trade for home tanks.

4

As well as natural forms, there are now multiple hybrids of this fish in circulation, most of which have terrible deformities.

3

While best suited to public aquaria, the young of these fish are often sold very cheaply as ‘kittens’ in the hobby to unwary aquarists.

2

Though it looks quite predatory, it actually feeds on a mixture of fish, fallen fruits and invertebrates, including freshwater crabs.

1

The largest-ever specimen of this fish was measured at 134cm long and weighed over 40kg. They are rumoured to get even larger in the wild!

(Answer on Tailpiece, page 114) WWW.PRACTICALFISHKEEPING.CO.UK 41

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TROPICAL Rummynose tetra

The

Rummynose

Trio

Some of the planet’s prettiest fish are right under our noses. Time to take a fresh look at the familiar Rummynose tetra trio. WORDS: STEVE BAKER

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PRACTICAL FISHKEEPING

WWW.PRACTICALFISHKEEPING.CO.UK 45

NEIL HEPWORTH

A Rummynose tetra – but which of the three is it?

TROPICAL Rummynose tetra

T

HE DOWNSIDE of being a household favourite is that it’s very easy to become overlooked. You can hang the most beautiful painting in your hallway and you’ll stand and stare at it many times during the first month. If it’s lucky, there might be appreciative glances for a few months more before it becomes part of the scenery. Other people, laying eyes on it for the first time, will be quick to show their enthusiasm, which might even re-ignite your love for the painting. Eventually, though, you just get used to having it around and it no longer gets the attention it deserves. There are quite a few tropical favourites I can think of that have fallen foul of the same issue as that painting. At least they have for me, which almost makes me feel envious of new fishkeepers. It would be great to have that excitement all over again! If I’d never seen a Rummynose tetra before, I’d be amazed at the sight of them – they’re a stunning, bright, active fish, and renowned as one of the best shoaling fish in the trade. The red nose steals the show,

but I’m just as taken by the flagstriped caudal fin myself. We see Rummynose tetras for sale in nearly all aquatics shops now and it’s been that way for years on end. They’re regarded as a trop tank staple and many think they’re well worth the small extra cost over tetras like Neons and Glowlights. So, Rummynose tetras are lovely, shoaling community fish, but once you’ve seen one, you’ve seen them all, right? Wrong! There are three described species that get sold under the common name of Rummynose tetra. Even if you see the scientific name displayed on the pricing label, it may be incorrect as identification at the exporter stage is rather unreliable, and nearly all imports are listed as Hemigrammus rhodostomus, rightly or wrongly. No need to panic, though. It’s not as if any of the Rummynose species

Because of its bolder head markings, H. belheri is most desired and also the most commonly sold of the three species.

When you’ve seen one, you’ve seen them all, right? Wrong!

grows into a 2ft-long, tooth-wielding predator, and there’s very little to tell them apart either physically or behaviourally.

MP&C PIEDNOIR, AQUAPRESS.COM

A very shiny nose

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PRACTICAL FISHKEEPING

So, what do we need to know about keeping these Rudolph-like pisces? The three species in question are Hemigrammus rhodostomus, H. bleheri and Petitella georgiae. They all overlap in Brazil as far as distribution is concerned, and they’re all happy in very similar conditions. In nature all three species are found in forest streams and rivers adorned with fallen tree trunks, branches, twigs and leaves that have got soaked and come to rest over a muddy or sandy

ABOVE: Bright shades of red are encouraged by a varied diet. LEFT: H. rhodostomus fights down a bloodworm. RIGHT: Although the red heads of these fish are duller, their stripy tails stand out.

Don’t forget their greens. Rummynoses are unlikely to tear a slice of cucumber apart, but they’ll nibble the edges of lettuce and blanched spinach leaves

base. Both the Hemigrammus species are found more often in blackwater conditions, where tannins have leached from the sunken flora and stained the water like tea. Tannic and humic acids leach and lower the pH of these forest streams. Micro fauna is abundant in the layers of leaf litter as bacterial and enzyme action breaks down the organic flotsam. Simple life forms such as rotifers and copepods feed on the bacteria, in turn being eaten by fish

MP&C PIEDNOIR, AQUAPRESS.COM

MP&C PIEDNOIR, AQUAPRESS.COM

MP&C PIEDNOIR, AQUAPRESS.COM

who are used to prepared foods. It’s well worth providing a wide variety of foods though. Not only will it boost health and vitality, but a varied diet will also go a long way to keeping those red noses bright. Feeding regularly with live or frozen Cyclops, Daphnia, black mosquito larvae and small brineshrimp will keep them happy and bright. It will also help if the dry food contains carotenoids (a natural red colour enhancer) and don’t forget their greens either. Rummynoses are unlikely to tear a slice of cucumber apart, but they’ll nibble the edges of lettuce and blanched spinach leaves – or just make sure their dried diet includes some vegetable matter. Rummynoses are In terms of aquarium equipment, regarded as top shoalers. Rummynoses are undemanding. They need the right temperature, basic filtration, some form of hide or cover, and little else. Being small, and other higher life forms. efficient fish, these tetras These three omnivores don’t produce much in the have small mouths, so we way of physical waste need to supply small and they’re quite food particles for Having larger but peaceful adaptable to them. They will different flow happily eat fish (like Festivum cichlids) will rates, so any style dried diets such encourage shoaling fish to of filter will suffice as flake food and swim together more as long as it’s suited micro granules – tightly. to the size of your tank. nearly all Rummynose Lighting isn’t essential but tetras for sale in aquatics it helps us to admire our fish. shops will be tank-bred fish

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TROPICAL Rummynose tetra

MP&C PIEDNOIR, AQUAPRESS.COM

Their natural habitats are dimly lit; the tannin-stained water blocks out the sun quickly if it manages to penetrate the forest canopy, but these tank-raised tetras are quite happy in brighter set-ups as long as there’s planting or some other cover, and they look great against a background of different greens. If you’re going with a well-lit tank, it’s advisable to use a dark substrate to contrast with the fishes’ markings. Pale substrates reflect the light and tend to wash their colours out, so go for black sintered glass, gravel, black sand or a dark planting substrate. Another thing that limits the Rummynoses’ colour vibrancy is hard, alkaline water conditions,

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and these will have an overall effect on the long-term health and life expectancy of your fish, as well as their colouring. The natural pH range of all three species spans from neutral (pH 7.0) down to an acidity of pH 5.5. With most of these fish being tank-bred. they’re more adaptable, but you should still provide a pH no higher than 7.5.

Tankmates When it comes to tankmates, the most difficult part for you will be making decisions. The three Rummynose species are peaceful fish. Occasionally they’ll have disputes within their own shoal, but these rarely end with any physical damage. One

limiting factor, though, is water values – there may be no argument between a Rummynose and a guppy, but they won’t suit the same conditions. The other thing is simply not to mix them with any fish that may pose a threat to them. Being slender tetras, I would avoid most fish of 10cm or more. While there are larger fish with small mouths, like Festivum cichlids, many bigger fish will revel in a taste of tetra. Often with shoaling fish, it’s more effective to focus on one species in an aquarium and go for numbers. A shoal of 20 Rummynose tetras will have much more visual impact than four groups of five different fish, and they’ll shoal tighter too.

FACTFILE RUMMYNOSE TETRA 6Scientific name: Hemigrammus rhodostomus 6Pronunciation: Hemi-gram-us road-oh-stow-mus 6Origin: Venezuela and Brazil: lower Amazon and Rio Orinoco basins 6Size: 5cm 6Tank size: 60x30x30cm for six (54 l) 6Water requirements: 5.5-7.0 pH, 2-15°H 6Temperature: 24-27°C 6Feeding: Flakes, microgranules, small live and frozen foods 6Availability and cost: Very common; around £3.50 each

HEAD The red is a far stronger colour than in Petitella georgiae. It covers the head, not just surrounding the eye, but confined to the head, not extending to the trunk of the body.

TAIL The true Rummynose has well-defined markings on the caudal fin that may bleed partly, but narrowly, into the body. This can be more reliable than head colouring, which is more likely to alter with mood and condition.

HEAD If the red head markings extend to the body, then it’s Hemigrammus bleheri – however, when stressed, this colour will fade and differences will be far less obvious. In general, the red colouring is stronger than seen on P. georgiae.

TAIL Hemigrammus bleheri displays three broken, dark bars on the caudal fin. Markings do bleed slightly into the caudal peduncle (or wrist), but do not extend to the body.

HEAD The head colouration on the false Rummynose is less vibrant than either of the other species and concentrated around the eye and mouth. Being less colourful in the head means P. georgiae is generally the least desirable Rummynose.

TAIL Three solid dark markings are present on the tail of the false Rummynose. Contrary to the others, a wide central marking extends well in to the body – an obvious sign for identification.

54 l+ FACTFILE FIREHEAD TETRA 6Scientific name: Hemigrammus bleheri 6Pronunciation: Hemi-gram-us blair-eye 6Origin: Brazil and Colombia: Rio Negro and Rio Meta 6Size: 5cm 6Tank size: 60x30x30cm for six (54 l) 6Water requirements: 5.5-7.0 pH, 2-15°H 6Temperature: 23-26°C 6Feeding: Flakes, microgranules, small live and frozen foods 6Availability and cost: Commonly sold as true Rummynose; around £3.50 each

FACTFILE FALSE RUMMYNOSE 6Scientific name: Petitella georgiae 6Pronunciation: Pet-it-ella georgeee-aye 6Origin: Peru and Brazil: Rio Purus, Rio Negro and Rio Madeira 6Size: 5cm 6Tank size: 60x30x30cm for six (54 l) 6Water requirements: 5.5-7.0 pH, 1-12°H 6Temperature: 22-26°C 6Feeding: Flakes, microgranules, small live and frozen foods 6Availability and cost: Often sold as true Rummynose; around £3.50 each

ILLUSTRATIONS: STEVE HALL-MAXTED

54 l+

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SPECIES SHOWCASE Halfbeaks

H

They’re odd looking, fragile and like to wrestle each other. But Gabor Horvath says they’re well worth the effort.

GABOR HOVARTH A Hungarian aquarist now living in the UK, Gabor is a prolific fish breeder, project undertaker and writer.

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there are still some significant differences between them that you need to consider if you want to keep and breed them successfully. The freshwater halfbeaks most frequently sold in the UK belong to the genera Dermogenys and Nomorhamphus, and here we’ll be looking at the former of those. These slender pike-like fish had been on my aquarist bucket list for ages, but for some reason I couldn’t get hold of any. Then my luck changed and I spotted a nice group of Wrestling halfbeaks at the JMC Aquatics’ stand at the Aqua Telford show. Fortunately they let me have 10 of them (thank you, Jane!) and

I could begin my halfbeak project. I’ve learned a lot about these interesting and very loveable fish in the past few months, so now it’s time to share this knowledge.

The trio The genus Dermogenys includes several species, such as D. pusilla, D. sumatrana and D. siamensis. The smallest and the least colourful of the trio is Dermogenys siamensis, barely reaching 4cm in length. In the other two species, the females can grow up to 7cm while the males stay a little smaller, peaking at 5cm. Colour-wise, the two larger species are quite similar, with the

Odd but not ugly. WWW.PRACTICALFISHKEEPING.CO.UK 51

GABOR HOVARTH

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HERE ARE beautiful fish and even more beautiful fish. There’s no such a thing as an ugly fish – I prefer to call them odd. The halfbeak family, hemiramphidae, got more than its fair share of oddity, with overgrown lower jaws and rugged heads – just take a closer look at them. Most of the halfbeaks are marine species, but there are a few interesting livebearer ones that spend their lives in freshwater or brackish-water environments. The halfbeaks available in the market share many similarities, but

SPECIES SHOWCASE Halfbeaks

males sporting orange or reddish dorsal and anal fins. The easiest way to tell them apart is based on the position of the ventral fins. In the case of the true Wrestling halfbeak, Dermogenys pusilla, they’re positioned around midway between the pelvic and the anal fin, while Dermogenys sumatrana has them closer to the anal fin. Wrestling halfbeaks can vary greatly in body colour, from the ‘natural’ silvery brown, through to gold, and to the almost white ‘platinum’ variety. All three Dermogenys species mentioned make appearances from time to time in the shops, and all are traded under the collective name of Wrestling halfbeak.

Fish that feed on foods that drop into their habitat from elsewhere are called allochthonous feeders.

Natural fighters The ‘wrestling’ moniker originates from the males’ keenness to get involved in territorial disputes with their rivals – a behaviour that’s especially prominent in wild-caught fish. Those long beaks serve a purpose – to decide who’s boss they grab each other’s beak and try to wrestle down their opponents. These fights can sometimes last over an hour, especially in the confined spaces of aquaria. In the fishes’ countries of origin, people use them for fish-fights, with bets placed on the outcomes, just as happens elsewhere with Siamese fighting fish. In aquaria this fighting spirit is unwanted, but with clever positioning of tank

FACTFILE WRESTLING HALFBEAK 6Scientific name: Dermogenys pusilla 6Pronunciation: Durr-mow-gen-iss pew-sill-ah 6Size: Females to 7cm, males to 5cm 6 Origin: Many countries, including Indonesia, Malaysia, Vietnam, Cambodia, Thailand, Laos, Myanmar and India 6 Habitat: Usually slow or still waters, canals, rivers, lakes and ponds 6Tank size: 90x45x30cm for a small group 6 Water requirements: Close to neutral – 6.5 to 7.5pH, hardness 5-15°H 6Temperature: 23-26°C 6Temperament: Males will spar with each other (wild fish more so), otherwise peaceful 6Feeding: Dried and frozen surfacefloating foods; flakes and pellets, bloodworm, mosquito larvae and Daphnia 6Availability and cost: Relatively common; starting around £3 each

120 l+

decor we can significantly reduce fight frequency by breaking up lines of sight and dividing the tank into distinct territories. My fish are fortunately quite docile, as they were probably tank-bred, so most of the time their sparring only goes as far as a bit of fin-flaring and mouth-gaping. Sometimes the females also join in the territorial disputes, but those don’t last for long. The plentiful floating plants (Salvinia) in my tank definitely help to reduce aggression, as they break up the lines of sight and also offer a retreat for the weaker fish.

GABOR HOVARTH

Making a home The natural habitats of the Dermogenys halfbeaks include slow-moving rivers and still waters in South-East Asia. Most of these biotopes have dense vegetation, with floating plants or submerged plants reaching up to the surface. Halfbeaks spend most of their time

MP&C PIEDNOIR AQUAPRESS

Halfbeaks are very interesting and challenging fish to keep and breed. I can strongly recommend them to those wanting something different

Bloodworm is a favourite food.

among this surface greenery, waiting for an occasional insect to fall in. Their elongated lower jaw and up-facing mouth enables them to quickly pluck the unfortunate fly from the surface. To keep them in peak condition we should provide them with a similar environment and diet in the fish tank. As Halfbeaks, especially those belonging to the Dermogenys genus, tend to stay near the top, the amount of surface area is much more important than the height of the aquarium. A fish tank with a 90x45cm base and a tight-fitting cover is perfect to house a small group of them. They’re very adaptable and can be kept in a range of water conditions, so long as the extremes are avoided and the water quality is pristine. Fill up their tank with water around 23-26°C, with a hardness of 5-15° and keep it close to neutral – 6.5-7.5pH – and you should have no problems. Keep the parameters steady, as these fish can be sensitive

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The ‘natural’ silvery brown male (below) and female (above).

SPECIES SHOWCASE Halfbeaks

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PRACTICAL FISHKEEPING

generally peaceful and can be kept well together with similarly sized community fish. Avoid boisterous fish as tankmates, as halfbeaks won’t withstand even light harrassment. Also avoid excessively small fish (like Boraras microrasbora), because they may be considered as dinner. I house my halfbeaks with Peacock gobies, Tateurndina ocellicauda, and it’s a match made in heaven – the halfbeaks always stay near to the surface, while the gobies occupy the lower regions, breeding away. Corydoras catfish, mollies, platies, small rainbowfish and deep-bodied tetras are all suitable tankmates.

BELOW: You can see where the beak will develop from in the fry.

Baby ‘beaks

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Persevere and in time your fish will to sudden changes in both acidity learn that your appearance means and temperature. Sometimes, halfbeaks can be found food and they’ll become braver. My Wrestling halfbeaks are always in brackish habitats in the wild, and the first to get to the food now, to mimic this some aquarists put a frequently poking my fingers with little aquarium salt into their water. their beaks to release their favourite It’s not essential though, and every treat of bloodworm. species discussed here will happily live and breed in completely freshwater tanks at the parameters Feeding and tankmates listed above as well. Halfbeaks are not very picky Decoration-wise, they’re eaters, as in nature they not very fussy. Basically, would grab anything they don’t care about edible falling into the anything below water, be that a Keep your halfbeaks at their eye level. worm, insect high temperatures to When choosing or plant. speed up spawning decor avoid hard If you imitate this rocks and other similar natural variety by cycles. blunt objects, which could feeding a range of frozen damage their beaks. meals – bloodworm, Artemia Beak injuries are quite frequent, or DIY frozen food – as well as as halfbeaks are easily spooked. flakes, floating granules and live When startled, they dart around the foods such as Daphnia, mosquito tank like tiny missiles, hitting the larvae and fruitfly, they will be glass or jumping out of the water eternally grateful. The only thing to altogether. So for the first few days remember is that if the food sinks after their arrival, be very careful further than 15cm or so from the when approaching their tank. surface, the halfbeaks will rarely Use lots of floating plants or other bother to follow it. To avoid water vegetation reaching the surface to pollution, it’s a good idea to keep help relieve this initial stress. Dense some cleaning crew with them to floating vegetation also helps if you pick up these falling morsels. want to breed them, as it provides Despite the pike-like, predatory protection for the newborn fry. appearance of halfbeaks they’re

Dermogenys halfbeaks are livebearers, but probably the hardest of the halfbeaks to breed. Even when successfully bred, the brood is quite small, consisting of only six to 20 youngsters after a 26-42 day gestation period, dependent on temperature. The difficulty isn’t getting them pregnant, as mature males make constant use of their andropodium – a modified fin-ray used as a reproductive organ, much like those of guppies – to ensure progeny. The problem is that females will give birth prematurely if frightened, or produce stillborn fry despite

GABOR HOVARTH

takes a few weeks before they begin to fully resemble their parents. Since my first success I’ve had several broods, the largest consisting of 14 fry. Luckily I didn’t experience any of the pregnancy issues, probably due to the extra care taken around water changes and a varied diet. The latter is a key factor to success. I did a small experiment to see the effect of feeding on the development of the juveniles. I divided one lot of fry into two, feeding the first group with high-quality dry food only, and the second with a variety of live and

frozen fare. Among the members of the first group, half of the fish became somehow deformed and even the rest remained much smaller than the ‘lucky’ fry in the second group. They obviously wouldn’t make ideal breeding stock. Wrestling halfbeaks are interesting and challenging fish to keep and breed. I can strongly recommend them to those wanting something a little different. If you’re prepared to go the extra mile and treat them well, I’m sure these happy halfbeaks will give you a smile.

ABOVE: Fry look suprisingly normal, not even quarterbeak. BELOW: Less striking, but the natural strain is more colourful.

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being given the best possible care. One reason often given for this is the lack of certain vitamins in the adults’ diet. I’ve always tried my best to provide my fish with rich food, which included regular portions of black mosquito larvae from my water butt. Nevertheless, I was still a bit nervous when I saw two of my females getting progressively plumper, which is a sure sign of an ongoing pregnancy. I’d read contrasting reports about adults preying on their fry, so to ensure the survival of the offspring, I moved one of the females to a well-planted separation tank when I thought the time was right, and divided my breeding aquarium into two with a hard plastic mesh to protect the newborns. I must have guessed the timing right, as next morning I found eight tiny silver ‘splinters’ hiding among the vegetation. Compared to the fry of common livebearer types like platies, these were quite large at around 6-8mm long. This meant feeding them caused no problem at all, as they accepted newly hatched Artemia and powdered floating flakes straight away. Interestingly the newborn fry of the halfbeaks have no beaks yet – they just look like a ‘normal’ fish. It

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THE EXPERTS

DR PETER BURGESS

TROPICAL

Is answering all your disease questions and suggests what to do about a shark with a suspected tumour on page 59.

BOB MEHEN Is answering all your community questions and considers why aquatics shops don’t sell ready-matured filters on page 56.

NATHAN HILL Is answering all your planted tank questions and tackles the difference between liquids and carbon dioxide on page 63.

Is answering all your cichlid questions and discusses breeding Electric blue Jack Dempseys on page 57.

NEALE MONKS Is answering all your biotope questions and looks at setting up a species tank for Bumblebee gobies on page 58.

DAVID WOLFENDEN Is answering all your marine fish questions, and explains how to set up a small, temperate reef tank on page 62.

Please do you have any tips for tempting my Raphael catfish to come out during the day? I have had him in a 450 l/100 gal large fish community with rainbows and barbs for about five weeks now, but he has wedged himself into a cave and all I’ve seen of him so far is his tail! I presume he’s coming out at night to feed, but it must be long after I’ve retired to bed as I’ve sat up after lights out and he hasn’t moved. PHIL THOMAS, EMAIL BOB REPLIES: As you are discovering, ‘talking catfish’ such as the Striped Raphael or Humbug catfish (usually Platydoras armatulus), are incredibly secretive, almost entirely nocturnal fish seldom seen out during daylight hours. To many catfish fanatics, me included, this is part of their charm – the fact that you might not see your bashful charges for weeks, even months at a time, only for them to suddenly make an unexpected, show-stopping reappearance! However, like most of us they can be

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encouraged to become a little more sociable with the right incentive, and I’ve always found they will stir from their hiding place – even during daylight – for a tasty treat, with bloodworm seeming to be a favourite. Gamma-irradiated frozen bloodworm is the best choice, being safe from the possibility of introducing something nasty to your tank, unlike the live alternative. Simply defrost a cube, drop it into the tank and see what happens. Your other fish will probably grab most of it, so you may need to add a couple of cubes worth. If your lights are on a timer then it’s best to add the cubes just before the lights switch off as the catfish is likely to be waking, ready for its usual nocturnal scavenging. It may take a few attempts to convince the catfish that it’s worth braving daylight, so it can also be worth dropping some in just after ‘lights out’ and watching to see its reaction. Use a torch covered with a red film so that you can see the catfish, but it can’t see you.

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JEREMY GAY

How do I encourage my catfish out?

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Every question we receive gets a reply from our experts. Include as much information as you can about your set-up. Photos are useful, too. 57

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Answers

Question of the Month Why don’t shops sell ready-matured filters?

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I’m completely new to the aquarium hobby and have just cycled my first 90 l/20 gal freshwater tank after a long period of research and conflicting advice. After weeks of ammonia, nitrite and nitrate testing I can’t wait to stock my tank, and dream of tackling the bigger set-ups and more exotic fish detailed in PFK every month. As a beginner, this may be a stupid question, but why do aquarium shops not sell already cycled ‘secondary’ filters that could be added to a new tank? PHILIP CAMPBELL, NORTHERN IRELAND BOB REPLIES: It’s great to hear of a new hobbyist thoroughly researching before taking the plunge; many people dive straight in with disastrous consequences. I’ve often wondered the same thing myself regarding cycled filters and media as clearly it would make things far more straightforward, as well as allowing newcomers to the hobby to add fish safely much sooner. Many years ago, I knew of a shop that did more or less what you suggest by offering mature filter media for customers buying a new filter. However, this initiative was short-lived. When I asked the retailer in question why they’d stopped, they explained that it was hard enough trying to get people to cycle their tanks before adding fish, and when they tried to sell the mature media, newcomers often thought it was some sort of con – ‘dirty’ secondhand media being handed over and the lovely, ‘fresh’, clean new media that came with the filter being taken by the shop! It all comes down to a lack of research by the customer. There is also the practicality of keeping lots of mature media alive for the purpose, especially when most shops sell a wide range of filter types and sizes, and foam media tends to be cut to a specific size. At the end of the day I suspect that this worthy and useful idea is just too tricky to implement, and it’s easier for shops to sell a customer wanting accelerated stocking a ‘bacteria in a bottle’ product and recommend low initial stock levels of hardy fish.

Send your questions to: Fishkeeping Answers, Practical Fishkeeping Magazine, Media House, Lynchwood, Peterborough, PE2 6EA. Email us at questions@practicalfishkeeping.co.uk

JACQUES PORTAL

TROPICAL

MARINE

Why is this media clumping?

TROPICAL

Will these fish breed true? I would like to keep a pair of Electric blue Jack Dempseys. Please could you tell me what size tank I would need and how to get a pair? Do they breed true? How should I furnish their tank and what should I feed the babies on? ROBERT SCOTT, EMAIL JEREMY REPLIES: Electric blue Jack Dempseys are hybrids and differ in head and body shape. They also won’t breed true, so some people pair them with a natural Jack Dempsey instead. Adult males will reach 20cm in length, with females smaller. A nice long-term home for a pair would be a tank in the region of 120x50x45cm, although I have bred medium-sized Jack Dempseys in a 75cm-long tank. Provide lots of substrate with rocks, wood and slate laid horizontally as they will dig everything up, and choose spawning sites and spare pits to move the fry to once hatched. Place a sponge over any filter inlets to prevent the fry being sucked in. I’ve raised Jack Dempseys on crushed flake food, which the parents then chew up further and present to the fry, but if I were doing it professionally and wanted fast growth, I would start them on newly hatched Artemia, and feed several times a day. Calanus is good too, and you will see the little bellies of the fry turning pink from feeding on it.

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NEIL HEPWORTH

JEREMY REPLIES: The K1 in the photograph looks pure white and brand new, and when it’s in that

state it will sit on top of itself at the surface and not move. It will take several days of soaking to bring it down lower into the water where it should be, or you can use a maturation gel to coat the media, also aiding sinking. Some long-term users also ‘mature’ K1 with potassium permanganate, a medication, which coats the media and provides a key for the bacteria to stick to. One common issue with K1 is actually using too much in relation to fish load. K1 loves load (it comes from the waste water industry) but using too much can mean maturation takes longer and the eventual biofilm is too thin (again causing floating issues.) Start with just a few litres of K1 and mature that first, then add a little more at a time if required.

DUNCAN GILL

I have an issue with the sump I’m building. I have designated one of the sections for K1 media, but after adding the K1, I’ve found that the media remains at the surface and doesn’t move or tumble. I have a large circular air stone attached to a Blagdon Koi pump which appears to produce enough water turbulence. I have tried moving this around but the pieces of K1 media just become stacked up on one another in a clump. I have included a photo (right) taken from above the sump to hopefully give you an idea of what is happening. Any advice would be greatly appreciated. DUNCAN GILL, EMAIL

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Answers

NEIL HEPWORTH

TROPICAL

How do I set up a biotope for Bumblebees? I have a tank that holds roughly 80 l/ 18 gal and I'd like to set it up as a single-species tank to keep Bumblebee gobies. I'd like to reflect the habitat they come from as much as possible so what would you recommend in terms of water parameters, furnishing and so on? How many will I be able to keep in a tank of this size please? ANNIE MATTHEWS, EMAIL NEALE SAYS: Defining the right habitat for Bumblebee gobies is tricky for two main reasons. The first is that most species are distributed across a range of environments, from blackwater streams to brackish mangrove swamps. In some cases, there are distinct populations, so you can get one batch of a given species that thrives in a normal freshwater tank, another batch that needs a bit of salt to stay healthy, while a third does better in soft and acidic blackwater conditions. The second problem is that there are numerous Brachygobius species that have been referred to as Bumblebee gobies over the years, and little or no effort is made to properly identify them on collection. So what you’ll see in your local fish shop could be one of several similar-looking species. Ichthyologists have gone so far as to state that the only way to safely identify Brachygobius species is by looking at their DNA. The Bumblebees you’ll see in aquatics shops are most likely to be one of two Southeast Asian species, Brachygobius doriae and B. sabanus. Since both species occur in freshwater and brackish water habitats, and have the same preference for small live and

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Air-powered sponge filters are ideal, frozen foods, distinguishing between and if the water currents are gentle, you them isn’t particularly important, and can use live Daphnia and Artemia to there are, in fact, lookalike species feed these fish with ease, and it’s from the same general area, such as usually feeding, not water chemistry, Brachygobius kabiliensis, that may get that makes or breaks Bumblebee goby imported from time to time. You could systems. Most Bumblebees that die set up the tank as a freshwater system prematurely do so from lack of food, or brackish water system as you prefer, not water chemistry, so while though medium hardness water with a discussions about their natural habitat neutral pH and a specific gravity are important, you shouldn’t between 1.001 and 1.002 is worry too much if you can’t probably a good default. ID the specimens in Regardless of water front of you – instead chemistry, both these focus on ensuring gobies come from your gobies get streams filled with One species you won’t see on sale regular offerings of vegetation and is Brachygobius xanthozona – the healthy live foods. decaying wood, so a In the right tank planted tank and fish most often seen in books. these gobies are lots of driftwood is Now called Hypogymnogobius not difficult to keep what you’re after. xanthozona, it is very rare and can be very Most plants tolerant of in the wild. rewarding, especially hard water will put up once they start spawning with a little salt without and you get to watch the males complaint, but hardy look after their offspring. Cryptocoryne species are perhaps the As far as stocking goes, 40-45 l/9-10 most authentic for this situation, such gal is probably ample for your first as C. wendtii, or the brackish-water half dozen specimens, and you’ll want specialist C. ciliata. to allow another 5-6 l/1-1.5 gal per Snail shells, ceramic caves, or hollow additional specimen, with the proviso ornaments of whatever kind will all be that you provide plenty of caves and used as shelter, with the males being visual obstructions to ensure the males very protective of their home territories, aren’t fighting all the time. as well as any eggs produced after You also need to keep a group, not spawning. Plants and wooden roots help just two or three specimens, to ensure to break up the territories, ensuring any territorial aggression is spread out rival males can keep out of each other’s and hopefully diluted by the presence way. The females are less territorial and of a sufficient number of females. may even form loose schools at times. So your 80 l/18 gal tank should Since these gobies are so small, they comfortably hold a dozen or so fish. don’t require a lot of filtration or space.

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ABOVE: Bumblebee gobies are small and full of character. A biotope setting will suit them best.

Send your questions to: Fishkeeping Answers, Practical Fishkeeping Magazine, Media House, Lynchwood, Peterborough, PE2 6EA. Email us at questions@practicalfishkeeping.co.uk

COLDWATER HEALTH

Does my shark have a tumour?

PETER SAYS: I agree this fish has some sort of tumour. The slow growth of the lump is typical of many tumours and, as you say, the fish appears to shows no other signs of ill-health and no obvious infections. Unfortunately, although the photos you

ALAMY

sent were very helpful, we are unable to say what type of tumour is causing the lump. To categorise the tumour would require taking a sample of the growth and examining the tissue under a microscope (using special chemical stains), which would be expensive and won’t affect the outcome anyway, given that we have no medications to combat tumours in fish. Depending on the type of tumour, it could spread to other parts of the fish’s body, or it may stay as a single mass. It could grow even larger and start to push or press on vital organs, causing significant harm or death. Or it may stop growing and cause no further discomfort or damage. On the plus side, the tumour won’t harm your other fish, even if it bursts. And the chances are it won’t burst. So, my advice is to do nothing, other than closely monitor the fish for any signs of abnormal activity, such as unusual swimming behaviour (including difficulty in swimming), lethargy, loss of appetite and so on. If it develops any of these abnormalities then that may be the time to consider having it put to sleep to prevent pain or distress. Also, ensure that none of the other fish in the tank are bothering it.

Can I keep a young Pike? Please can you tell me whether it is possible to keep a young native Pike of approximately 15cm in an aquarium, just over the winter? If so, what should I feed it? SHAUN BUCKLEY, EMAIL JEREMY ADVISES: If overwintering a native Pike, I would actually do it outside, perhaps placing the aquarium in an unheated garage or shed. The inside room temperature will be far too warm, especially if the room the aquarium is located in is centrally heated, so you would probably need to invest in a chiller. Wild-caught Pike will not be used to feeding on anything that isn’t alive. I don’t believe in or recommend feeding live fish, so try river shrimp and earthworms or, if you are lucky, you might be able to get it to take whitebait thrown onto the surface and moved so that it looks alive. It will take time and perseverance to get a Pike onto dead foods or even dry foods, but it is possible, and by far the best long term. As when fishing for them, it’s all about how you present that food to start a strike or feeding response. You may even need to be out of the room, or hiding behind the door, and use actual fishing line (minus the hook!) and wiggle the food around.

HOWARD DAVIES

I have a Red tail black shark that is around five years old. I got him when he was very small and until recently he was developing and growing well. But around six months ago a lump started to grow on his upper left flank. It has continued to get larger and is now quite a size. I’m assuming it is some sort of tumour. He is in a 200 l/44 gal mixed community tank that is well established and all his tankmates are healthy and active. Is there any danger of the growth bursting and damaging the other fish in the tank? I’m wondering at what point euthanasia might be appropriate. He eats well and his behaviour is unchanged. There are no secondary infections such as finrot, fungus or dropsy, swimbladder fine, so I don’t think he is under any particular distress at the moment. I’d appreciate your advice. HOWARD DAVIES, EMAIL

Wild-caught Pike will not be used to feeding on anything that isn’t alive

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Answers POND

Why won’t my pond’s nitrite level fall? nitrite 0.03mg/l and nitrate 50mg/l. I live in East Devon, with decent hard water but a high nitrate level. I am surprised my pH is considerably higher than my tapwater and wonder if this is affecting bacteria colonisation of the K1? I have tried EA Pond Bombs and used EA Filter Start but this doesn’t seem to have any effect. It may just be a time thing, as I’ve noticed the K1 is only just beginning to colour up. Your advice would be most welcome. KAI ROCKLIFFE, EMAIL

Below: Longterm nitritre readings could be down to inaccurate tests.

NEIL HEPWORTH

I'd like to ask your advice regarding a stubborn nitrite level I just cannot shift in my 3,047 gal Koi pond. The pond was completed and filled in the summer of 2017, but due to ongoing building work I only added the first three 20cm fish in May this year. The pond is covered all winter with an untreated wooden frame (sealed with G4) with 10mm twin wall polycarb sheet and heated with an air source heat pump. I run a Nexus 310 with 40 l of K1 in the central chamber and 150 l of K1 in the biological chamber. The pond has an EA 35 UV after a Blue Eco 750 pump set at 2,200 rpm. Two returns at opposite ends, one low and one below the water line, give good variable flow and keep the pond clean. I also have a Spindrifter aerated bottom drain. The first three fish were thriving, so I added two more 30cm Koi in early July. Everything is working well and the fish are happy, healthy and growing. Ammonia levels are zero but I have been unable to lower my nitrite to less than 0.03 mg/l. Nitrate is a constant 50 mg/l, pH a constant 8.2 and KH 184. These never seem to fluctuate, so at least there are no swings in values. It's worth noting my tapwater is pH 6.8,

JEREMY SAYS: With an identical nitrite level of 0.03ppm in both pond and tap, I would say that this is down to the accuracy of your nitrite test kit, and that you actually don’t have any nitrite level at all. If it was higher than that and you only had three to five fish, I would actually advise removing 100 l of the K1 from the outer chamber of the Nexus, as the surface area will be so great in relation to fish load, proper biofilm development would be hindered as it would be so thin. But I wouldn’t worry about that nitrite level, especially if your fish look happy. Regarding the pH, it may be worth re-checking your tapwater pH at different times of the day and even different times of the year, and also seeing if letting it stand makes a difference, with CO2 gassing off and oxygen diffusing in. If the pH remains consistently lower than in your pond, then something is raising the pH, be that some ceramic filter media somewhere, or a blanketweed treatment perhaps. Check there is no concrete in contact with the water anywhere from the pond design and build, or any water course.

TROPICAL

Which gourami would best suit this tank?

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BOB SAYS: Gourami are very underrated fish – over-familiarity sometimes means fishkeepers ignore what are actually some of the most brightly coloured, attractive community fish available. An excellent candidate for your tank would be the Pearl gourami, Trichopodus leerii. These are gorgeous, graceful mid-sized gourami that reach around 12cm and don't generally have the aggression issues associated with their similar-sized cousin Trichopodus trichopterus, the Three spot/Blue/Opaline gourami. Your tank has a volume of around 200 l/44 gal, so unless it has unusual dimensions that mean it is tall and thin, then you should have room for a group of three – ideally two females and one male. They

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appreciate a well-planted tank (floating plants are also a good idea), with some open swimming space and only gentle water movement.

Pearl gourami, Trichopodus leerii.

Send your questions to: Fishkeeping Answers, Practical Fishkeeping Magazine, Media House, Lynchwood, Peterborough, PE2 6EA. Email us at questions@practicalfishkeeping.co.uk

ALAMY

I have a community set-up that needs a feature fish or two. It holds approximately 45 gal and has been set up for four months. It has a mix of real and fake plants and lots of branchy wood with fine gravel at the bottom. It has a Fluval filter. Stock includes 10 Harlequin rasboras, three platies, seven Cherry barbs, four Otocinclus catfish and six Sterbai cory catfish. I’m also planning to get a Peppermint plec or something similar at a later date. I would quite like some larger gouramis for this tank as feature fish. Which would be the best choice? Dwarf and Honeys are a bit too small. Also, how many can I keep? Are they best in pairs or groups and will my other fish be compatible with them? DAVE STUART, EMAIL

Which halfbeaks are best for brackish tanks? I’m planning a future brackish tank and have been trying to get some solid information on brackish halfbeaks, including their sizes and water parameters. Please could you offer some advice? NATHANIEL BULLOCK, EMAIL NEALE SAYS: Halfbeaks are very common in estuaries and mangroves all around the world – the problem for us aquarists is that relatively few, if any, of those species are regularly traded. The one truly brackish water genus of halfbeaks that has been traded is Zenarchopterus, in particular, the River halfbeak, Z. buffonis. While these are very rarely imported, they do appear on the stock lists offered by wholesalers, so those retailers who specialise in importing oddballs and rarities may be able to get them in as a special order. Zenarchopterus are quite large – 15-20cm is typical – and highly social, which means you’ll need a big aquarium able to provide a safe home for a school of these nervous, easily injured fish. They appreciate strongly brackish water, with a specific gravity of 1.005–1.010, and require very clean water with plenty of water movement and oxygen. When it comes to the common halfbeak species seen in aquarium shops, those divide up into three groups – the Wrestling halfbeaks, Dermogenys spp., the colourful Sulawesi halfbeaks, Nomorhamphus spp., and the Bearded halfbeaks, Hemirhamphodon spp.. We can dismiss Hemirhamphodon immediately. All are more or less blackwater specialists that inhabit rainforest streams. They have little tolerance for hard water conditions, let alone brackish. Although very attractive, they’re best suited to expert fishkeepers willing to set aside an aquarium that caters to their special needs. Nomorhamphus species are the most commonly seen halfbeaks, especially the lovely Celebes halfbeak, Nomorhamphus liemi. Again, we’re dealing with species adapted to freshwater environments. While they aren’t too fussy about water chemistry, provided extremes are avoided, they’re not commonly reported from brackish water. Things become more interesting when we get to Dermogenys. Although mostly found in freshwater, they’re also quite common in brackish streams, and will tolerate slightly brackish conditions indefinitely, provided all else is amenable to them. I wouldn’t recommend keeping them at a specific gravity above 1.003, but that still makes them perfectly viable candidates for a mixed species set-up that includes other small, peaceful fish species. They’re especially good companions for gobies and flounders because they offer no competition at feeding time. You could also keep them with any small livebearers that need brackish water to do well, such as Micropoecilia species. Identifying Dermogenys is a bit hit-and-miss though, despite the widespread use of the name Dermogenys pusilla to describe any Wrestling halfbeak offered for sale! Luckily, they’re all pretty similar in terms of care. Medium hardness freshwater, with or without a little salt, seems to work well, along with good water quality. Like all halfbeaks, they’re nervous but quarrelsome, so keep a reasonable number (at least six, with females outnumbering males) and provide them with some overhead shade, but also plenty of open swimming space where they can feed without being harassed by their tankmates. Adult size varies. Males reach around 4-5cm depending on the species, but the females can get quite a bit bigger, 7-8 cm in some cases, and are far more stocky in build than the slender, even scrawny looking males.

Will corys clean my dirty gravel? I have a 70 l/16 gal tropical tank with an Interpet PF2 filter. It’s currently stocked with five Lemon tetras, three Cherry barbs (I’m hoping to get another), a bent Silver-tip tetra that has survived a year, an 18-month-old female guppy and a tiny female Bristlenose catfish I've had 10 months. I'd like to get some Corydoras catfish to stir up my sand which, despite regular stirring, is becoming quite stagnant. My nitrates are quite high, so I don't think Panda corys are best. I’ve been considering Dwarf or Pygmy corys. Would they suit my tank and how many should I have? ESTHER CLARK, EMAIL BOB SAYS: As you suggest, Corydoras can be helpful in gently stirring up sandy substrates to keep them clean. However, if your tank's sand is becoming stagnant it's worth looking at the causes of this before adding the catfish, as a stagnant substrate can be bad for their health. How deep is the sand? Unless you’re growing lots of plants, I would recommend a shallow bed of 2cm maximum. This way it’s unlikely to compact, and fish like the corys can easily dig it over so it shouldn't become stagnant. You mention high nitrates, so it may be worth upping your water changes. The maximum amount allowed in tapwater is 50mg per litre, so even if you live in an area with readings that high, you should be able to keep your tank level below that with weekly 25% water changes. Using a 50:50 mix of RO and tapwater for changes can also help keep the reading down in high nitrate areas. If your tapwater doesn't have a high level of nitrates, then this points to possible overfeeding or lack of water The Pygmy cory, Corydoras changes, as well as pygmaeus, is lively, but won’t dig too-deep substrate. in the substrate to any great Corydoras panda degree. It’ll happily rest on plants should be fine in your tank if you can keep or swim in midwater. your substrate clean and nitrate below 40mg/l. Ideally, you need a group of at least five.

ALAMY

TROPICAL

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NATHAN HILL

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MARINE

How do I set up a small temperate reef tank?

DAVE SAYS: The Catalina goby, Lythrypnus dalli (right), is an absolutely stunning fish, with its bright red body and electric blue stripes. They’re small (topping off at about 6cm), and benefit from a system tailored to their needs, so a dedicated nano tank is perfect for them as they can get lost in larger tanks. Crucially, this is a subtropical species as you’ve pointed out, being found around the Pacific coast of the Americas from the top of Southern California down to Peru. This means they require cooler water temperatures than we’d keep

NEIL HEPWORTH

I have a tank of approximately 72 l/ 16 gal which I would like to set up for keeping Catalina gobies. I understand they are temperate, so I’d like to know the best temperature and specific gravity (SG) and how best to set up the tank. Will live rock still work at a lower temperature and are there any inverts (mobile and sessile) I can keep with them? What about live sand – will that be OK? How many gobies can I keep together (they will be the only fish)? I have kept a reef tank in the past and it was quite successful, so this wouldn’t be my first attempt with marines. WILL, EMAIL

typical reef inhabitants. Ideally, you’re looking at an optimal temperature of 18°C, with a maximum of 21°C. Higher temperatures lead to stress and shortened lifespans, and also obviously

limits potential tankmate choices too. It’s definitely possible to keep them, however – you’ll need a chiller, and the tank should be decked out with a mixed sand and rubble substrate for these

I have tried to keep Daisy ricefish now on two occasions but they keep getting whitespot. I have a 45 l/10 gal tank with a heater, the filter is cycled and water quality is always good. The tank is planted with long-stem plants so the fish have lots of hiding places. There is also some bogwood and a gravel substrate. I have been keeping fish for eight years and have two other tropical community tanks that run without problems, but I just can't get these fish right. Please could you tell me what they need so I can work out what I'm doing wrong? I really like them and would like to breed them eventually. LUKE, EMAIL

TROPICAL

Why can’t I keep these ricefish successfully?

ALAMY

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Answers

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EVERYTHING YOU NEED FOR HEALTHY FISH

NEALE SAYS: Ricefish are normally quite easy to keep, but there are one or two things to think about before you try. The first is water chemistry. Daisy ricefish, Oryzias woworae, may well be adaptable up to a point, but slightly hard, neutral to slightly basic water chemistry

Send your questions to: Fishkeeping Answers, Practical Fishkeeping Magazine, Media House, Lynchwood, Peterborough, PE2 6EA. Email us at questions@practicalfishkeeping.co.uk

PLANTS

Am I dosing enough ‘carbon dioxide’? I’m trying to improve growth of my plants by using liquid carbon dioxide, but I know that an overdose is harmful to fish, and my plants don’t seem to be growing any better now that I’m using it. Just how much can I go safely over on the dose rate before I hurt my fish? TREVOR FARRIS, EMAIL NATHAN SAYS: There’s no such thing as a safe overdose as far as the fish are concerned. Your product will have been tested to a standard called an LD-50, which is the dose at which half the study sample of organisms it was tested on died. This is then used to calculate a safe dose. Cutting to the chase, what you have there isn’t liquid carbon dioxide, it’s a carbon dioxide alternative, and while some of it eventually decays into carbon dioxide, that’s not what it is. The active ingredient in most of these liquids is something called glutaraldehyde, and it’s potent stuff. Not all plants get on with glutaraldehyde, and the likes of Vallisneria in particular tend to die rather than thrive where it is used.

be used during spawning seems to suit them best. If as well, the females adding a little aquarium depositing their eggs salt is necessary to among them one stymie whitespot, a When trying to breed ricefish, at a time. But therapeutic dose enrich their diet for a few days also of use is the of 2g per litre will beforehand with Daphnia, cover the plants do them no harm brineshrimp, fruit provide, sheltering at all, even across newly hatched fry from many weeks. They don’t flies or Grindal the potentially need salt, of course, but at worms. cannibalistic adults. this very low dosage it’s an I’ve never found ricefish easy way to inhibit whitespot difficult to feed, with all the usual without the need to use any other small fish foods being welcomed, medications. It’s just possible that including powdered flake food, some standard whitespot medications have proved toxic in your situation, as is Daphnia, even frozen lobster eggs! But their small size, slow swimming speed, sometimes the case with sensitive fish. and generally shy demeanour does The second thing to bear in mind mean they will lose out if kept about ricefish is that they come from alongside other surface-swimming sluggish streams and pools, rather than species, such as danios. rivers. The ideal aquarium for them Far better to keep them on their own, will have very gentle filtration – an with the tank tailored to their specific air-powered sponge filter is probably the needs – in other words, with floating ideal – as well as numerous clumps of rather than rooted plants, and sluggish floating vegetation. Needless to say, the rather than brisk water currents. roots and leaves of floating plants will

If you see your plants dying while using liquid carbon, chances are there’s an incompatibility, especially if the leaves become transparent and start to dissolve. If they turn other colours, then it’s more likely a deficiency of some essential nutrient. Before writing off the liquid carbon, check that the other parameters are all in line. Are you using enough fertilisers for the tank? Are you providing enough of the right kind of light for the plants to grow? Is there adequate circulation, and is the substrate a plant-friendly type? Beyond that, are you trying to grow particularly slow or difficult plants? There are many factors at play here. If everything else is suitably plant-friendly, then I’d suggest trying injecting actual carbon dioxide into the tank. While daunting at first, it’s actually pretty easy to use once you have been hands-on with it, and it is surprisingly economical over time. In my own experience, liquid carbon and carbon dioxide works well together. I had a planted tank where I used both and a heavy fertiliser regime, and the plants grew so fast they were almost a nuisance!

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If you struggle with Oryzias woworae, it might be worth trying the Indian ricefish, Oryzias dancena instead. This hardy and inexpensive ricefish is often sold as Oryzias melastigma, so you might find it available under that name. Regardless of this taxonomic confusion, it’s a pretty fish with beautiful electric blue markings on the fins which, in the case of the males, are elegantly extended into lacy threads. It’s very easy to keep and breed, and makes a great choice for planted nano tanks.

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primarily benthic fish. This could be live sand, and the micro-organisms on the sand will survive at these slightly lower temperatures. As far as live rock is concerned, you can expect much of the life on reef live rock to survive in the range of 18°C-21°C, although some of the ‘macro’ life may experience die-off, particularly towards the lower end of this range. You’ll just need to keep an eye on this, and monitor water quality in case it’s impacted. Clean-up-crew and mobile invertebrates might be tricky, although genuine subtropical species such as the Margarita snail (Margarites pupillus) are sometimes available. Salinity for Catalina gobies is exactly the same as for a typical reef tank – 32-33ppt, which at 18°C is around 1.024 SG. While one specimen can be kept in a 72 l/16 gal aquarium, do bear in mind they can be quite territorial, so it’s best to consider 150 litres or so if you’re thinking of establishing a pair or trio. Alternatively, a tropical goby might be worth considering as you’ll have more choice for tankmates, including mobile invertebrates and perhaps even some small corals. The tiny (2.5cm) red striped goby, Trimma cana, from the western Pacific springs to mind here. It’s a very attractive and peaceful fish, perfect for a nano system, and it does well in small groups if several are introduced simultaneously.

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SETTING UP

EXTERNAL FILTERS Lots of people are daunted by external filters, but they’re easier to set up than you might think. Here are the essentials you need to know… WORDS: NATHAN HILL

Some filter designs come with a heater built in. These require extra care when removing the head, as a jarring move will break the heater. To control the heater, the thermostat will be somewhere on the filter exterior, probably on a dial or similar.

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XTERNAL CANISTER filters are great. They’re big, which means they can house a lot more media than internal filter types, and that in turn makes them more efficient and versatile. They’re also conveniently placed out of view, underneath or beside the tank where they’re not an eyesore. Over the following pages we’re looking at three different canister filters, and the parts of them that seem to cause confusion.

Aquamanta EFX200 The Aquamanta EXF 200 is the smallest in the EFX range and suitable for tanks from 100 l (comfortably) up to 200 l (at a stretch). Once out of the box, there are a few things you need to do to get it up and running.

1

Unclip the four clasps holding the lid in place. To do this, pull them outwards from the bottom and then slide them in an upwards direction. Once you’ve loosened all four clasps, you can remove the head.

4

Remove the three media baskets. One contains a mesh bag filled with carbon – leave this as it is. One a block of foam – leave this. The third contains biomedia balls in a plastic bag. These MUST be removed from the bag before use. Briefly rinse them under a tap to remove dust.

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Next position the canister’s head unit on top of the body so that the protruding ‘spout’ underneath the head aligns with the downpipe. Don’t try to push it into place at this stage. Just concentrate on aligning it the right way round.

How to prime Most canister filters will not start unless they’re already filled. The easiest way to do this is to remove the canister head and use a jug to fill the body with water from an aquarium. When filled, replace the head, ensure the hoses in and out of the tank are connected and the valves open, and vigorously push up and down on the priming (or start) button while the filter is running. After a big blast of bubbles, everything should run just fine.

2

Turn the head upside down and find the impeller well chamber. Twist the cover of the well anti-clockwise and gently pull it away – be careful not to pull out at an angle as you risk snapping the impeller shaft, which may be attached as shown in the photo above.

5

Place the three media baskets back in the canister – carbon at the bottom, biomedia balls in the middle and foams on the top. Ensure that all three trays are aligned so that the downpipe runs neatly through all three.

8

Now gently push the head unit down. If it doesn’t sit flush, remove and replace the baskets and try again. DO NOT force the head unit down. Once it’s sitting comfortably, secure the head unit in place with the clamps.

3

Remove the impeller and inspect for damage such as cracks or broken vanes. Reinsert the impeller and replace the impeller well cover, making sure that the ceramic shaft fits neatly down the middle of the impeller. Twist the cover clockwise to lock it in place.

6

Find the plastic grid in the packaging. Place the grid on top of the top media basket (the one containing the block of foam and fine foam pad), so that the canister filter’s downpipe is exposed.

9

Insert the hose connection assembly into the slot in the head, with the central lever in the ‘up’ position. Push the lever down to lock it into place and open the valves. (Lifting this lever locks the valves, retaining water in the pipes and stopping syphoning when disconnected.)

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Aqua Medic Aqua Fresh 50 This small and visually appealing filter is robust and capable of filtering between 75 l (comfortably) and 150 l (at a stretch). However, it has no priming facilities, which makes it tricky to start. With limited media inside, this product is likely aimed at planted aquascape keepers. As this filter has no priming mechanism, in order to start it you need to syphon water through it. Attach one hose to the tank, and lower the other one below the water level, into a bucket. Start a syphon action (you can buy handpumps to do this) until the filter and all hosing is filled with water. Reattach the hose used to syphon and turn the canister on. Alternatively, you can use a funnel to pour water down the hoses until the canister and hosing is filled. Note that to access the impeller you will need to remove the pump unit from the canister and this requires a screwdriver.

Open the filter by pulling the fastening clips away from the canister. The metal clasps will now lift away from the holding attachments on the filter head.

2

Once you’ve removed the head, arrange the media inside so that the little metal stand sits on its legs at the bottom of the canister. Place the black sponge on top of the metal stand, and the white sponge on top of the black sponge. Hold both in place with the metal spacer and then replace the lid, clamping it back down.

3

This filter comes without valves, strainers or water-return accessories, so buy these to your taste (aquascapers tend to use glassware for filters like this). To connect the hoses, push them over the inlet nozzle (at the bottom) and return nozzle (on top) using the provided hoseclips to secure them in place.

4

Connecting hoses Assemble any inlet and outlet pipes – downpipes and strainers at one end of the tank, spraybars or duckbill returns on the other. Cut hosing to fit and attach by pushing it over the stem and then clamping down with the threaded nut. (See photo right). Connect your hoses to the filter valves the same way (using the locking nut to secure them). Note that nozzles marked ‘IN’ are for water coming from the aquarium, and those marked ‘OUT’ are for water leaving the filter and going back to the aquarium. (See right).

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Tight hosing can be softened by immersing it in hot water for 20 seconds or so. This makes fixture and fitting a lot easier.

Biomedia fact Biomedia loses efficiency if it becomes impregnated with waste and may need replacing. Do this over a prolonged period, removing up to a quarter of the media in one go and replacing with fresh. Repeat every four weeks until the media is replaced entirely.

JBL CrystalProfi e902 The e902 is a terrific all-round canister filter with a flow that makes it suitable for tanks of between 90 l (comfortably) and 300 l (at a stretch). Because of its low wattage (11w max consumption) it’s also one of the most economic filters on the market.

1

Carbon adsorbs organic waste until its holding capacity is exhausted, so in a relatively clean tank it may last for months; in a dirty tank, just weeks. The industry standard is to replace the carbon entirely every six weeks.

2

Remove the head unit by unfastening the four clips holding it. Pull them away at the bottom and then slide upwards until they release.

4

Turn the head unit over and then remove the impeller well cover by gently twisting it in an anticlockwise direction.

5

Remove the four media baskets from the canister body and check them. Two of the baskets should contain plain blue foam, one a block of corrugated blue foam, and the fourth contains the biomedia balls.

7

Place the basket of biomedia balls in the bottom of the filter. Place the two plain blue foam baskets above, making sure they align. Finally place the basket with the corrugated blue foam on the top.

8

To attach the hose connection assembly, there are three levers. Ensure that the two levers on the canister body are set to the ‘closed’ position, and the central lever on the assembly is in the ‘lifted’ position.

Now firmly push the hose connection assembly into place. Ensure that you push down the central lever on the assembly FIRST so that it locks into position.

3

Remove the impeller and inspect for damage such as cracks or broken vanes. Reinsert the impeller and replace the well cover, twisting clockwise to secure it.

6

Attach the head, making sure the wide spout fits flush with the aperture on the top basket. Use the clips to secure the head to the canister body. If the head isn’t sitting flush, remove the baskets and check alignments.

9

Once the assembly is locked, push the two smaller levers to the ‘open’ position. This will open the valves inside the assembly so that water can flow through it.

Connecting spraybars

Don’t lose the cap! Some spraybar assemblies come with a loose cap that needs to be inserted into one end if the spraybar is to work properly.

Some spraybars have multiple parts that need to be connected together with a short length of rubber hose. Note that the longer you make a spraybar, the less flow you will have from each outlet.

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JACQUES PORTAL

Sand, gravel, soil or enriched clay – what’s the best choice of substrate for your tank and your fish?

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NEALE MONKS Neale is an aquatics author with a passion for brackish water species.

LAVA ROCKS

COLOURED GRAVEL

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HOOSING THE right substrate is one of the most important decisions to make when setting up a new aquarium. There are so many options available that it’s easy to end up with the wrong kind or, at least, one that doesn’t work out quite as well as you’d hoped. Replacing substrate is an expensive and time-consuming process, so it’s something you’ll want to get right from the off. In some cases, the choice of substrate comes down to personal taste, but often, the best one for the job really depends on what fish you’d like to keep or which plants you’re trying to grow.

NO SUBSTRATE PLAIN GRAVEL

PLANTING SUBSTRATE SOIL

COLOURED SAND

SILICA SAND

NO SUBSTRATE

Leaving the tank bare is a good option for tanks where cleanliness is the number one priority. This includes breeding tanks, hospital tanks and quarantine tanks. Pros 6Faeces and decaying organic matter are easily syphoned out during water changes. 6Medications circulate around the aquarium more effectively, making it harder for pathogens to survive. Cons 6Looks unattractive. 6There’s nothing to shore up rockwork or piles of bogwood, so you need to use self-supporting ornaments and caves, such as flowerpots.

6There’s nothing for plants to root themselves into, so you’re limited to artificial plants, floating plants, or epiphytic plants attached to bogwood or rocks. 6Overhead light will reflect upwards off the glass bottom, stressing the fish and causing them to exhibit subdued or washed-out colours to try to blend in.

they forage for food. Sharper grades of gravel may cause so much damage that the fish become prone to bacterial infections. 6While stirring the gravel helps when cleaning out dirt and debris, plant roots will make it harder to do this properly. 6It’s devoid of mineral nutrients, so provides little benefit to plants beyond anchorage.

PLAIN GRAVEL

COLOURED GRAVELS

For decades this was the default choice, usually on top of an under-gravel filter plate, where the gravel acted as the biological medium. While still a popular choice (and rarely a bad one), think about the alternatives before going down this route as plain gravel does have some shortcomings.

These are usually smooth gravels that are painted and then covered with an aquarium-safe varnish. While not to everyone’s taste, they’re often popular with children.

Pros 6Cheap and easily obtained. 6Lime-free gravel from aquatics shops is chemically inert, so it won’t change the pH or water hardness. 6Numerous grades available, from fine pea gravel ideal for small fish communities, to almost pebbly gravels less easily disturbed by jumbo species. 6Its dark colour minimises upwelling light, enhancing the colours of your fish. Cons 6Scratches and shortens the whiskers of catfish and loaches as

Pros 6Lots of colours to choose from. 6Darker gravels, particularly black, can highlight certain fishes’ colours. 6Chemically inert, so won’t change the pH or hardness of the water.

Can you mix substrates? There’s no reason why you have to stick to one substrate throughout the entire aquarium. Mixing silver sand and fine gravel, for instance, creates something that resembles river gravel, which would be ideal for a biotope housing Australian rainbowfish and other river species. Or, you could use one substrate over most of the tank, but put a plant-friendly substrate into plant pots hidden behind rocks and bogwood. This is a good way to get the benefit of expensive substrates without spending too much money.

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Cons 6Unnatural in appearance – and can look a bit naff! 6Brighter colours, particularly white, reflect light upwards, which can stress fish and cause them to exhibit subdued colouration. 6Fish with delicate colours look dull next to red, blue and other vivid gravels. 6Don’t contain mineral nutrients for plants. 6Pricier than plain gravel.

SILICA SAND This lime-free sand is chemically inert and widely used by gardeners. There are two types available – sharp sand and smooth (or silver) sand. Don’t use sharp sand as it will scratch bottom-dwelling fish like loaches and catfish, but silver sand can work very well if cleaned thoroughly before use. Silver sand is also marketed as pool filter sand, which is usually much cleaner than the smooth sand sold by garden centres. Pros 6Inexpensive and easy to obtain. 6Makes a fabulous substrate for tanks with catfish, loaches, and other burrowing or digging species. 6Natural in appearance, and a great choice for biotope tanks. 6Won’t cause a change in the pH or hardness of the water. 6Set up correctly, deep sand beds become partially anaerobic, fostering the growth of denitrifying bacteria that can lower nitrate levels. Cons 6Contains little in the way of mineral nutrients, though plants will root readily. 6It reflects some light upwards, so some fish will show weaker colours. 6Big fish can move it about, potentially undermining rockwork. 6Some sand may end up in the filter if the filter inlet is too close to the substrate. 6Sand will scratch the tank if caught between the glass and an algae scraper. 72

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COLOURED SANDS Some are artificial, some natural, and some are industrial by-products. Whatever their origins, they look superb in the right tank, offering more variety than plain silica sand. Pros 6Usually chemically inert – but check with the manufacturer. 6Various dark shades are available, including black volcanic sand that can look absolutely fabulous in planted aquaria, showing off the subtly coloured fish and shrimps to best advantage. Cons 6Dearer than plain silver sand. 6Some are too sharp, so they aren’t suitable for burrowers like catfish and loaches. 6Some types contain mineral nutrients that enhance plant growth, but most of them don’t.

SOIL We don’t recommend you dig up your garden, but natural soil products from aquarium shops are useful for helping to replicate the substrates found in rainforest streams or pools. Pros 6Very naturalistic, especially with

What about using peat? In the past, peat was widely used in aquaria to create rainforest biotopes – much like aquarium soil, but with the added benefit of softening the water and reducing the pH. This was seen as a good way to create the conditions required by species like killifish, who would lay their eggs in the peat, enabling it to be removed to another tank before hatching. However, peat is an unpredictable tool for softening water, and has been almost entirely replaced by RO filtration. More importantly, peat harvesting is unsustainable. Peat bogs develop slowly across many many thousands of years, and cannot support industrial peat extraction. If you come across an older aquarium book that recommends peat, use aquarium soil instead and manage the water chemistry in whichever way you prefer.

some Catappa leaves and bogwood roots added. 6The dark colour enhances many fish, especially those with fluorescent markings. 6Tends to tint the water over time, further enhancing colours. The tea-coloured water is particularly appreciated by blackwater habitat species, such as Discus. 6Burrowing fish love it and behave in a very natural manner –

BELOW: A stark contrast between a naturalistic look and colourfully adventurous.

LAVA ROCK CHIPPINGS This is similar to the large pieces of ‘lava rock’ sold as decoration and makes a good alternative to plain gravel. Pros 6Lighter than gravel. 6It has a porous structure, which allows slow movement of water through the substrate. This creates partially anoxic conditions that foster the growth of denitrifying bacteria, and maintenance of non-oxidised mineral ions that plants can use. 6Open structure, so good for under-gravel filters and tanks with substrate heaters.

ALAMY

Cons 6Better in tanks with small fish. Larger fish will disturb the soil, making the water murky and potentially clogging the filter inlet. 6Contains some mineral nutrients, particularly iron, but this varies between brands, so you might need to use additional fertiliser. 6Quite expensive, although in tanks without rooted plants you only need enough to cover the bottom glass.

ALAMY

especially elephantnoses and spiny eels, which don’t thrive in tanks with gravel substrates. 6Plants root quickly, as you would expect.

6Rough texture forms a secure base for securing bogwood and rockwork. 6Dark in colour, so shows off fish well. 6Some types include minerals for good plant growth, though periodic use of fertilisers may still be needed. Cons 6Rough texture, which can cause damage to burrowing fish. 6More expensive than gravel.

PLANTED AQUARIUM SUBSTRATES Often based on mineral-enriched clay, which slowly releases beneficial minerals around the roots of your plants. Plants are more fussed about light intensity than anything else though, so if your tank doesn’t have strong lighting, a fancy substrate won’t make much difference.

Pros 6The best choice for aquariums with rooted plants. 6Vigorous plant growth is the easiest way to avoid algae problems, so plants that get their nutrients from the substrate, rather than from the water column, will really appreciate this stuff – as will your tank and fish. 6The better brands are guaranteed to last for five years before needing replacement. 6Fine and smooth, so good for burrowing fish. 6Dark brown, so works well against the colours of your fish.

ABOVE: The wrong substrate can destroy catfish whiskers.

Cons 6Very expensive, although this is offset by the reduced need for periodic fertiliser dosing. And the better plant growth means that you won’t be replacing your plants every few months!

Can I use coral sand? Coral sand is mostly sold for use in marine aquaria, but it does have some niche applications in the freshwater side of the hobby. Because it’s made up of calcareous minerals, such as aragonite and calcite, however, it will harden the water and raise the pH, so it’s not suitable for normal community tanks. For fish from hard water environments, like Malawian and Tanganyikan cichlids, it’s ideal. On the other hand, because coral sand is bright white, it’s not a good choice for fish that dislike upwelling light.

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HONEY, I HURT THE FISH Whether you’re new to the hobby, or fancy a refresher, here are the most common fishkeeping mistakes to watch out for... WORDS: STEVE BAKER

Not preparing water correctly

NEIL HEPWORTH

The chlorine, fluoride and heavy metals that occur in tapwater all present problems for aquatic life. Use a good dechlorinating fluid or carbon-filled canister to neutralise or absorb these unwanted compounds when doing a partial water change. Untreated tapwater will kill beneficial filter bacteria and irritate fishes’ gills and skin.

Scratching glass

Buying a too-small tank It’s understandable to think that spending less money on a smaller tank is a good way to find out whether you like the hobby or not. The reality is that reduced volumes of water fluctuate more, and small tanks are restrictive, harder to maintain and hold little value secondhand. Although a 70 l tank might cost £30-40 more than a 30 l tank, the equipment is similar, it won’t need much more by way of maintenance, there’s lots more you can do with it, and a 70 l tank has a far better resale value if you decide fishkeeping’s not for you.

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Location, location, location Spending time deciding where to site your new aquarium could save a lot of headaches later. Avoid placing the tank in direct sunlight. This will encourage algae to grow over your ornaments and plants – or the water might just turn bright green. Keep it away from vents and radiators, which will affect the tank’s stable temperature. And don’t place it near a busy door – regular movement and banging will disturb the inhabitants. Also, make sure there’s power nearby.

Adding substrate straight in When you’re full of enthusiasm, it’s tempting to put in new gravel or sand straightaway, but it needs a thorough clean first. Most substrates are very dirty and the ‘dust’ will cause water quality issues. NEIL HEPWORTH

If you’re new to fishkeeping, it’s all too easy to scratch the inside of a pristine, shiny aquarium. Often, it’s down to cleaning, and getting a piece of gravel between your sponge/ magnet and the glass. Be very careful not to pick up any stray bits around the substrate layer; even a single grain of sand can leave an obvious scar.

NEIL HEPWORTH

ADVICE

Know-how

Introducing fish too quickly

NEIL HEPWORTH

It’s tempting to put new fish straight into your aquarium so you can watch them, but patience is a virtue in aquatics and a slow introduction is best for your fish. First, turn off the light to keep your new fish calmer. Float the bag in the tank to equalise the temperatures, then open it (rolling the bag down so it floats), and add small amounts of tank water regularly, over an hour or so, to introduce the fish to your tank conditions. Catch the fish with a net, and discard the transport water. Leave the lights off for a couple of hours so that your new introductions settle in with minimal stress.

Not researching fish Many fishkeepers have fallen foul of buying a fish on a whim only for it to cause destruction in a community tank before outgrowing it. Unfortunately, ‘tankbusters’ are being regularly offered for sale again, so you really need to be aware of what you’re buying. If you don’t know, ask – but ideally, do your own research. You must be prepared to care for every fish you buy long-term and within the guidelines of the Animal Welfare Act 2006.

Turning the power off It still happens. If you haven’t been told to leave aquarium equipment running 24/7, then you might not realise, but heaters and filters need power all the time (other than during maintenance) to keep balanced conditions. This is why prolonged power cuts can be catastrophic for fish.

Correct dosing of your aquarium will be important, so whether you’re using filter-boosting bacterial remedies, or medicating for parasites or bacterial ailments, you need to know how much water your tank holds. Overdosing some medications can lead to toxic shock and the death of your fish; under-dosing could fail to treat an issue, potentially leading to advanced problems and possible loss of fish. To calculate the volume, use the sum: Length x height x width (in cm), divided by 1,000 = volume in litres. Then deduct 10% for substrate and ornament displacement. Alternatively, just measure how many litres of water you add the first time you fill up your aquarium.

Leaving the lights on Some people miss the point that lights need to go off at night for the good of the fish and the aquarist. Although fish don’t fully sleep, they do enter a transient state that’s as important to them as sleep is to us. Constant illumination will ‘burn out’ the inhabitants, as well as causing lots of algae growth. If you can’t programme your lighting, you can use a simple plug timer to stick to the same photoperiod each day. (It also looks like you’re at home when you’re not.) Just be careful not to use a digital timer with an LED light. Some LEDs don’t like it and the light unit might be damaged.

Know your water Soft or hard, acid or alkaline? These make big differences to fish health, so test your tapwater to find out which fish are best suited to it. Unless you want the extra challenge of altering your water chemistry, of course.

NEIL HEPWORTH

NEIL HEPWORTH

Know your tank volume

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JACQUES PORTAL

ADVICE

Know-how

Feeding the wrong food With an estimated 34,000 species of fish in the world’s waters in 2018, there are some very different approaches to aquatic life out there, and diet is a major part of that. Don’t assume all your fish have the same culinary needs. Research the correct diets for each fish you’re considering keeping, and look at the ingredients of prepared, dry diets before you buy.

Not cleaning gravel I’m surprised by the number of people who use a jug to remove tank water, or just syphon water from the top half of the tank when doing water changes. Water changes are the perfect opportunity to syphon settled waste from the lower water column and vacuum your gravel to remove trapped waste. Don’t vacuum gravel if there’s plant substrate below it. And if you’re using sand, just rake your fingers through it, then syphon out any disturbed waste.

Replacing an old filter with new

NEIL HEPWORTH

This applies to the filter as a whole, or just the filter media. It’s easy to think removing an old, dirty filter and putting a nice, clean one in its place is a sound idea but it’s not. Filter bacteria are THE most important part of any tank and they need time to colonise a new filter or media. Either have both running for six weeks before removing the old filter, or remove the media from the old filter and place it in the new one (in other words, transferring the bacteria). Replacing a sponge? Change no more than 50% at a time. Cut it in half if needed, and wait six weeks before changing the second half.

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Over-cleaning

It’s a common dilemma. You go on holiday, a neighbour pops in to feed the fish, and a week later you get home to problems. Fishsitters tend to overfeed, not realising the effect this can have on water quality. Even if they have fish themselves, they won’t know your tank or how much you normally feed. Strategy 1: Buy a one-week pill box and put your normal daily serving in each compartment. (And hide the rest of your fish food). Strategy 2: Most common aquarium fish can go a week without food, so you could add live plants to nibble on and leave them be. Strategy 3: Automatic feeders can be very useful, but set one up a few days before you go away to check the settings.

There’s rarely a good reason for large-scale overhauling of fish tanks. Draining tanks, rinsing or boiling gravel and ornaments, and keeping fish in a bucket in the meantime, are all ways to upset the biological balance of the tank and stress your fish. Little-and-often water changing and cleaning is the way forward. Even if things have got on top of you lately, a small clean each day for a week is far better than one big overhaul.

NEIL HEPWORTH

Holiday feeding

Buying the wrong plants

Aquatic plants are just like other plants – they use lots of different elements for growth and we need to provide them. Fish waste will provide some food for plants, but liquid additives or nutrient-rich substrates should be used to provide both major and minor elements needed for lush growth. Lighting is also very important for plants, so make sure your bulb produces around 6,000 kelvin for better results.

Many aquatics shops still stock and sell unsuitable ‘aquarium’ plants. Common houseplants like Dracaena, Caladium, peace lily, parlour palm, spider plant, Fittonia, Ophipogon, Acorus grass and some ferns which just rot away underwater. This causes pollution of the tank and encourages people to replace them, spending unnecessary money. What to look for? Fleshy stems – and remember, no variegated plant belongs underwater.

SHUTTERSTOCK

Not feeding plants

NEIL HEPWORTH

Washing filters in tapwater After building up a colony of healthy filter bacteria, the last thing you should do is clean your filter with tapwater. The chlorine will immediately kill the colony and water quality will deteriorate rapidly, along with fish health. Instead, wash filters in a bucket of water taken from the tank during your water change – they don’t need to be spotless.

Your biggest allies in keeping fish are filter bacteria, but they aren’t present in a brand new filter. Before you add any fish to a tank you need a colony of bacteria and there are two ways to do it. ‘Cycling’ is the act of adding organic waste to give bacteria something to feed on in the absence of fish waste. Household ammonia is most often used (raising levels to 4.0ppm), but some fishkeepers use fish food products. Monitor the water parameters and perhaps add live bacteria to secure a colony. Once water test results are good (which normally takes four to six weeks), you can start stocking. The other option, if you have a fishkeeping friend, is to transfer some mature Contaminated filter media from equipment their filter to yours, Using the same bucket for adding a small group of fish cleaning the aquarium and the car is at the same likely to be disastrous for your livestock. Play time. Mature it safe and buy a new bucket, pipe, sponge and media net to be used on the aquarium only. If moved into an you run more than one tank, it’s empty tank will best to have separate die back unless fed with fish waste. equipment for

NEIL HEPWORTH

Not cycling your filter

each one. WWW.PRACTICALFISHKEEPING.CO.UK 77

TROPICAL Mormyrids

ELECTRIC ELEPHANTS With their distinctive trunk-like snouts and bigger than average brains, elephantnoses are intelligent, unforgettable oddballs.

SHUTTERSTOCK

DAVID WOLFENDEN Dave is a former aquatics lecturer and is curator of the Blue Planet aquarium in Chester.

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Demanding but rewarding, the elephantnose needs an experienced keeper. WWW.PRACTICALFISHKEEPING.CO.UK 79

TROPICAL Mormyrids

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huge diversity across the group. When the term ‘elephantnose’ is mentioned, most fishkeepers think of species with a highly moveable, protruding snout – the wonderfully named schnauzenorgan, used for detecting food in muddy or sandy substrates. The morphology of this appendage varies according to the predominant substrate type in the species’ habitat. But not all species have a schnauzenorgan; there are also blunt-nosed species that tend to feed in mid-water, rather than near the bottom, and have more of a dolphin- or whale-like appearance.

Friends electric Schnauzenorgan or no, all elephantnoses are weakly electric fish. This means they generate an electric current from an organ in their caudal peduncle – essentially highly modified muscle tissue. Mormyrids generate pulses of electricity – typically 20 pulses per minute at rest, as opposed to the constant waves produced by South

American knifefish, although the general principle is similar. The head, plus the dorsal and ventral parts of the fish’s body, are covered in very sensitive electroreceptors that can detect the electric field generated, which is known as the electric organ discharge (EOD). Objects entering the EOD field create distortions that the mormyrid can detect and interpret, and the degree of distortion varies depending on whether the object is inorganic

BELOW: G. petersii is the most common and most suitable elephantnose for home aquaria.

FACTFILE PETERS’ ELEPHANTNOSE 6Scientific name: Gnathonemus petersii 6Pronuciation: Natho-nee-mus peter-sea-eye 6 Origin: Widespread over central and western Africa 6 Habitat: Slow-moving areas of dark, muddy rivers with heavy plant growth. 6Size: 35cm max, rarely more than 25cm 6Tank size: 200x45x45cm for five 6  Water requirements: 6.0-7.5 pH, 5-15°H 6Temperature: 24-28°C 6Cost: Around £15 each.

400 l+

ALAMY

W

ITH THEIR bizarre and unforgettable looks, unique behaviour and incredible ability to ‘see’ using electricity, the elephantnoses truly deserve their oddball status. While they can make incredible aquarium subjects, they’re also somewhat cryptic and demanding, so you need to put a lot of thought into catering specifically for their needs. Elephantnoses belong to the Mormyridae family, which currently contains 228 recognised species. All come from Africa and are found in a variety of freshwater habitats – in some locations they’re extremely abundant. None are found in brackish water as even slight levels of salinity raise the conductivity of the water, affecting the fish’s electrosensory abilities. The strange appearance of the mormyrids gives these species a definite wow factor, but there is

(a rock, for example), or organic (such as a predator or prey). The EOD is an amazing adaptation to a nocturnal lifestyle in turbid water and is used for navigation, foraging and communication. Using the EOD, mormyrids appear to be able to distinguish between different materials in the water, and even whether prey is alive or dead. EODs are species-specific, and also vary between male and females of the same species, playing a crucial role in courtship behaviour. Mormyrids are intelligent fish, having proportionally large brains and a well-developed and specialised cerebellum with a tightly folded portion known as the valvula cerebelli. The convoluted, ribbon-like morphology of this part of the brain gives it the huge surface area needed to process the

highly complex information the fish attains from the EOD. Unravel the valvula cerebelli of a mormyrid, and it’ll stretch to over 10 times the body length of the fish itself.

Water parameters Mormyrids are sensitive to changes in water chemistry, so provide stable conditions – a mature, fully cycled system is a must. They will need a temperature of 24-28°C, with zero ammonia and nitrite. Aim to maintain nitrate as low as possible, too. Medium hardness and a pH of 6.0-7.5 suits them fine. Treat water with a conditioner, and ideally age the water by aerating and pre-heating it over several days before performing water changes. Mormyrids have been shown to have exceptionally high oxygen

Elephant drums As well as the EOD, mormyrids also communicate through a complex system of clicks generated by their swimbladders. Specialised muscles ‘drum’ on the swimbladder to generate sound, and some species appear to have evolved ‘hearing aids’ known as tympanic bladders. These tiny gas-filled structures brush against the fish’s ear bones in response to external noise, amplifying the sound and significantly boosting hearing sensitivity.

demands (necessary to maintain their huge brains) so you need to ensure adequate turnover and aeration to maintain oxygen as near saturation levels as possible.

Choosing & quarantining

BELOW: G. schilthuisi, a rare ‘short snout’ type.

When buying mormyrids, select your specimens very carefully. Elephantnoses can suffer damage or be generally stressed by shipping, so you need to closely inspect them in the flesh. Ensure they’ve settled

MP&C PIEDNOIR, AQUAPRESS.COM

With their bizarre looks, unique behaviour and incredible ability to ‘see’ using electricity, the elephantnoses truly deserve their oddball status

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TROPICAL Mormyrids

We Recommend... Tankmates Diurnally active species that feed in mid-water, such as the Congo tetra, Phenacogrammus interruptus, can work well with elephantnoses. They don’t do their best when housed with other nocturnal species, or with lots of bottom-feeding fish who tend to outcompete them for food. I’ve seen different mormyrid species housed together with seemingly few problems, but on balance it’s probably best to keep them in single-species tanks to reduce hetero-specific aggression. Some aquarists keep them with South American knifefish, such as the Black ghost knifefish, Apteronotus albifrons, but obviously this isn’t a natural mix and can cause issues with competition and aggression.

LOCATION OF ELECTRICAL ANATOMY

Elephant house

Electroreceptors Central nervous system Electric organ

NATHAN HILL

in at the dealer’s, and look for full-bodied individuals with no signs of emaciation. Ask to see them eating if possible – a good mormyrid should be actively foraging and greedily feeding. Elephantnoses are often imported with internal and/or external parasites, so quarantining new specimens is highly recommended. The quarantine tank can be kept quite dark, allowing the fish to settle in and adapt to captive diets before being moved to the main aquarium. Mormyrids are scaleless fish, so they are very sensitive to medications. Most of the common treatments that might safely be given to other fish are a no-no, including copper and formalin. Even salt will cause issues, although praziquantel appears to be safe if treatment for flukes is required. In general, resting the fish with minimal disturbance, ensuring that they feed in the first few weeks, and maintaining optimal water quality is the best way to get them in good health. For the quarantine system, you’ll need a pre-matured filter and be prepared to perform small, frequent water changes. Substrates are often omitted in quarantine systems on hygiene grounds, but with elephantnoses it’s essential to include one.

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Elephantnoses need a set-up that caters for their particular and exacting requirements. They don’t fare well as an afterthought addition to a community tank, and now that aquarists and responsible stores have wised up to this fact, they are thankfully not offered for sale as frequently as they were a few years ago. Mormyrids need larger tanks than many people think. The most commonly offered species, Gnathonemus petersii, needs at least a 2m-long tank for a group of five or so, slightly less for an single specimen. Overall volume is less important than area, and the bigger the better – these are definitely not fish for a nano tank. They’ve been known to jump when startled, so a coverglass, lid or hood is a wise precaution. Being nocturnally active and well-adapted to murky water, mormyrids may become stressed in gin-clear, brightly lit aquariums if they’re unable to hide, so provide

FACTS & STATS The largest mormyrid is Mormyrops ang the Cornish jack It’s widespread across Africa an extensively fished Adults can reach 1.5m in length and weigh in at a whopping 15kg.

15 KG

NEIL HEPWORTH

<1volt

is the EOD of mormyrids and presents no risk to aquarists, unlike the infamous electric eel, Electrophorus electricus, which can discharge several hundred volts.

20 plenty of cover and dimly-lit areas. Stable rock caves are a good addition and can be safely built around pieces of PVC tube for a discreet, natural look. Soft, fine sand in which the mormyrid can search for food is an absolute must. Too often, elephantnoses are placed in systems with coarse gravel, which is totally unsuitable. Large, rough-grained substrates can damage the sensitive snout and make it difficult for the elephantnose to forage. Add some smooth cobbles and wood to help the fish feel at home. Thoughtful planting can add visual interest and provide excellent cover for mormyrids, although the bright lighting you need for some plants may cause the fish to hide, so you’ll need to strike a balance. A planted system suitable for mormyrids could have focused spots of plant-rich zones, with other areas left relatively dimly lit. Suitable African plants include Anubias species, which can be placed in the substrate or attached to wood, and

African water fern, Bolbitis heudelotti, which needs to be placed on rocks or tied to wood.

Feeding mormyrids The largest mormyrid species are predatory, but those offered in the trade tend towards smaller prey such as larval and adult insects, plus small snails and crustaceans. That large brain requires a lot of fuel, and mormyrids can rapidly lose condition if their feeding needs aren’t being met. A well-fed elephantnose should have a slightly plump appearance – if the body isn’t slightly rounded, the fish needs more food, and if the body looks hollowed-out, then it’s in real trouble. Ideal foods for mormyrids include bloodworm, tubifex and glassworm, plus crustaceans like Daphnia. These should preferably be live when the fish are newly introduced to encourage feeding, but once settled, they will accept frozen and freeze-dried versions (although quality live food is best).

ABOVE: A shoal of elephantnoses turn the sand over while feeding. LEFT: The Worm-jawed mormyrid grows to 40cm.

pulses per minute at rest is typical of mormyrids.

Female elephantnoses have shorter electrical pulses than males.

2cm

is how deep into the ground the electrical organ can sense if a bug is dead or alive when looking for food.

10

times the length of the body is how long the valvula cerbelli would be if unravelled.

35cm

is the length Peters’ elephantnose can reach in the wild.

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TROPICAL

Elephants need cover and areas of darkness.

Breeding blues Breeding mormyrids is a challenge, although studies on Brienomyrus brachyistius suggest courtship can be initiated by lowering the water’s conductivity from around 300 μS cm-1 to about 20 μS cm-1 by adding de-ionised water. Breeding follows, with nest-building and egg deposition. However, that’s not the whole story. While newly caught specimens of several species appear to readily breed in laboratory conditions, success with longterm captive mormyrids remains elusive. A classic study on Gnathonemus petersii provides some clues. After only two weeks in captivity, the EODs of male and female fish became identical, meaning courtship will not be initiated effectively. After a month, the fish changed physiologically. Marked hormonal changes were observed, with some females exhibiting higher testosterone levels than males. This goes a long way to explain why long-term captive mormyrids are so difficult to breed.

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Provide as much variety as possible and experiment to a degree, but do keep an eye on the condition of the fish to make sure they’re receiving adequate nutrition. Importantly, these fish can’t efficiently chew their food, so large pellets and meaty chunks won’t cut the mustard.

Peters’ elephantnose Of the 200-plus known mormyrid species, only a handful make it to the aquarium trade, and one species makes up by far the vast majority of individuals imported. Peters’ elephantnose, Gnathonemus petersii, comes from the Niger and Congo basins and for most aquarists, it’s the quintessential elephantnose fish. In terms of looks, G. petersii is quite attractive compared to certain other members of the family – it’s not exactly pretty by any stretch of the imagination, but it has interesting bar-like markings on the posterior half. It varies from light brown to black in colour, and there’s sometimes a subtle iridescence

when it catches the light. The fish’s most obvious feature is its prominent schnauzenorgan – see one in action searching the substrate and you’ll understand why providing soft sand is so important. G. petersii can reportedly reach 35cm in length, but most aquarium specimens rarely exceed 25cm. Even so, that’s still a big fish that needs a considerable amount of room, especially if it’s going to be kept in small groups. Keeping pairs can be problematical as two individuals may fight incessantly, so aim for five or even more fish if space permits. The feeling here is that aggression is spread out in a group, so no one individual is targeted (much the same way as Malawi cichlids fare best in densely stocked tanks). Some aquarists suggest that while sub-adults may tolerate one another, aggression and territoriality increases as the fish reach sexual maturity. This isn’t always the case, but providing adequate space and hiding places can reduce any problems.

NEIL HEPWORTH

Mormyrids

Assorted elephants While Gnathonemus petersii is the species you’re most likely to see in aquatics stores, others occasionally find their way to specialist dealers.  MORMYRUS KANNUME This species is relatively widespread across Eastern Africa in a variety of habitats, including Lake Victoria and the Lower Nile basin, but is not often imported. It has a drab grey colouration, a relatively long dorsal fin and a fairly short snout, which gives it its common name, the Bottlenose. A solitary species, it feeds extensively on chironomid (midge) larvae and can reach 1m in length, although 50-60cm is a more typical size. Obviously, it needs an extremely large system to accommodate it.

CAMPYLOMORMYRUS TAMANDUA  The Worm-jawed mormyrid from West and Central Afr can reach 40cm, so it needs a very large system – ea 2m-long for a single adult. Coupled with the fact it’s intolerant of conspecifics in captivity, this is probably fish for most folks to avoid. Juveniles are quite attrac with disruptive colouration, but this fades in adulthoo and the fish assumes a uniformly drab colour

 CAMPYLOMORMYRUS RHYNCHOPHORUS The Double-nosed elephant fish gets its name from the distinctive morphology of its schnauzenorgan. It’s a peaceful, gregarious species that’s rarely seen in the trade, but can make a good choice in the right system. It comes from the Congo River basin in Central Africa and grows up to 20cm in length.

STEVE HALL-MAXTED

BRIENOMYRUS  Members of the Brienomyrus genus are occasionally imported from West and Central Africa. All three recognised species are relatively small, growing to 10-20cm, but classification for the genus is still unresolved, so identification can be difficult. They lack a prominent schnauzenorgan, which gives them more of a whale-like appearance, but in spite of their cute looks, they can be territorial and are best either kept singly, or in groups of five or more in larger tanks. They’re bottom to mid-water feeders, and need a diet of Daphnia, bloodworms and other invertebrates.

MARINES Jawfish

SHUTTERSTOCK

TRISTAN LOUGHER Tristan is an aquatic author who has worked on various research projects. His day job is at Cheshire Aquatics.

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It may look terrifying, but it's only a male jawfish incubating his eggs.

PRACTICAL FISHKEEPING

JAW They live in burrows, the males look after the eggs, and they can puff up their mouths to look big if threatened. Welcome the jawfish.

MARINES Jawfish

W

HILE WE should be careful not to project human attributes onto the fish in our care, some really do seem to have wonderful characters and a unique, fishy ‘personality’. Many are also beautiful, some are pretty disease resistant, and there are even species that offer the opportunity to spawn and rear them at home. Some of those types can be found within the fabulous jawfish of the Opistognathidae family. The Opistognathidae is a group of small to medium-sized marine fish that range from just a few centimetres in length to around half a metre – specifically, a species originally named the Giant jawfish, Opistognathus rhomaleus. There are currently four genera contained within the family, of

Blue spoed jawfish

NATHAN HILL

6Scientific Name: Opistognathus rosenblatti 6Provenance: Eastern Pacific; Sea of Cortez 6Cost: £150-250 6Maximum Size: Around 12cm

A desirable species commanding a high price. This subtropical fish can be reclusive when stocked without members of the same species, but its territorial aggression means aquaria need to be very large to accommodate more than one individual comfortably – a 100cm distance between burrows is the average in the wild. Otherwise, it can fit well into aquarium life, but check individuals are settled and feeding before purchase.

which one, Opistognathus, accounts for the vast majority of species, with over 65 currently described, and is also home to all of the species available in the hobby – it's represented by species from all around the globe. The other genera are Lonchopisthus, a group of largely deeper-water jawfish restricted to the subtropical and tropical Atlantic; Stalix, a genus where all member species are found in the Indo-Pacific; and a more recent addition to the family, the genus Anoptoplacus – currently represented by a single species, the tiny, deepwater Caribbean pygmy jawfish, A. pygmaeus. The jawfish’s common name derives from the size of its head, which can be 'inflated' through muscular contractions to appear substantially large, and make the fish look more of a fearsome proposition to predators than it actually is.

Housing and feeding Jawfish have a well-developed sense of place; a phenomenon called site attachment. They aren’t natural roamers, instead finding a place they like and staying there – often for the entire duration of their lives. Many of the best fish for marine aquaria are those for whom natural territories could be contained within the confines of a fish tank and many jawfish tick this box. There has been much written on the requirements of jawfish with regard to minimum depths of substrate but, as with so many aspects of the marine aquarium hobby, any generalisation only tells part of the story. In their natural environments jawfish reside in burrows that they excavate and tend to themselves. These can differ in composition and form between species and also are influenced strongly by the types of substrate available to a particular individual.

Jawfish can burrow in many types of substrate.

which they will inhabit when other areas of the aquarium seem to offer a more textbook habitat for them. To closely simulate their natural environment, deeper substrates with a mixture of rubble, sand and gravel are preferred, but these aren't always favoured by aquarists. Jawfish love to dig and fuss about their burrows, and watching them do this and then return to sit inside their latest creation is part of the enduring appeal of these fish. However, placing them into a well-established aquarium can cause problems as they disturb detritus-bearing sand by digging and can potentially undermine rock structures. It’s a

SHUTTERSTOCK

SHUTTERSTOCK

Many texts concerning jawfish stress the need for substrate depths of between 7cm and 15cm as an absolute minimum. The truth is that many species will make do with only a fraction of this, and some are highly resourceful in what they will use to construct a burrow in which they feel at home. I've seen certain Caribbean species pull substrate from all over the aquarium to construct a conical burrow, with an opening at the top that gave it an appearance much like a volcano. Others seem happy beneath rocks and in crevices that they fill and shape with rubble and sand from the surrounding locale,

Yeowhead or Pearly jawfish The most commonly available jawfish in the hobby is the best studied and most widely kept. It has been successfully spawned and reared in captivity. Colonies of four to six individuals can be kept in an aquarium of 200 l with adequate floor space. Broods are incubated by the male for seven to nine days before the eggs hatch. At just 15 days after hatching, the fry undergo metamorphosis and begin building their own burrows.

SHUTTERSTOCK

6 Scientific Name: Opistognathus aurifrons 6 Provenance: Western Central Atlantic 6 Cost: £20-35 6 Maximum Size: 10cm

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MARINES

remarkable resilience when placed in aquaria with the likes of tangs and dwarf angelfish. But, as with so many fish combinations, compatibility can be highly context-specific – placed with jawfish, aggressive species like dottybacks and some wrasse often go on to be bullies. It pays to make jawfish an early addition to any set-up, allowing them time to create a place to call home and develop it in a relatively sedate environment. Add the busier fish afterwards and your jawfish will feel much more secure.

Breeding

Male jawfish typically court females before spawning and it's then that any differences between males and females can be observed. The Blue spotted jawfish male, for example, develops a white front half, while Tankmates the rear part of his body turns Although it's difficult to argue almost black as he darts up that jawfish will thrive in and down in the water otherwise-peaceful column – this is his aquaria with a handful way of displaying of boisterous Due to their digging, it's his readiness tankmates best to introduce jawfish into – something to mate. In aquaria before the sand has that’s pretty O. solorensis the much true for all female appears a chance to hold too fish – they can show bright yellow during much organic

waste.

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PRACTICAL FISHKEEPING

Dusky jawfish 6Scientific Name: Opistognathus whitehursti 6Provenance: Western Atlantic 6Cost: £25-40 6Maximum Size: 14cm

Although not the most colourful species listed here, the Dusky jawfish is perhaps one of the best candidates for sole residency in a reef aquarium. It will dig, but appears highly resourceful in its choice of burrow material and can incorporate practically anything into its structure. As with many species of jawfish, providing a range of substrate sizes, from sand grains to gravel and rubble, assists the fish in creating a lasting burrow that it feels safe in. It settles well but care should be taken when housing it with small fish as they could definitely be on the menu.

Tiger or Blackcap jawfish 6Scientific Name: Opistognathus randalli 6Provenance: Indonesia and the Philippines 6Cost: £32-40 6Maximum Size: Around 12-14cm

For most aquarists, a single specimen of this hardto-sex species will be plenty. Males are known to be highly aggressive and prone to wrestling bouts featuring jaw-locking – the loser is quite likely to be evicted from his burrow. The gold appearance of the upper portion of the eyes can be useful for identification purposes – because of this, the species is also known by the lt ti name of 'gold-specs' jawfish. e and this is a beautiful fish to care um.

SHUTTERSTOCK

shame as jawfish are reef-safe and can be trusted with all but the tiniest fish and ornamental shrimp, and are otherwise wonderful aquarium fish. However, the biggest hazard for a jawfish is probably an open-topped tank. Use of a lid is compulsory to prevent them from leaping from aquaria. Jawfish are particularly nervous when first stocked into the aquarium and it's no coincidence that it's during the first weeks after introduction that they're most likely to be found outside the tank. Some jawfish are planktivores whereas others consume a variety of benthic invertebrates – small crustaceans and worms. Some include small fish in their natural diet. Most, if not all, should readily accept frozen diets such as Mysis and brineshrimp in the aquarium and many can be weaned onto flake and pellet diets.

CREATIVE COMMONS

Jawfish

ABOVE: Breeding can take place in his burrow, hers or a halfway house.

Red headed jawfish 6Scientific Name: Opistognathus solorensis 6Provenance: Eastern Indian Ocean to Tonga Central Pacific. 6Cost: £30-40 6Maximum Size: Around 8-10cm

One of the most popular species in the UK hobby, the Red-headed jawfish is sold under various common names. It is hardy once settled and can be maintained in groups where space allows; offer around 300-400 l for four to six individuals. Supplies of these fish can be a little sporadic; sometimes one or two may be available, then there's an abundance of them.

SHUTTERSTOCK

the breeding season. Unfortunately, these visual cues aren't likely to be displayed by fish in shop tanks, so buying a group and allowing them to sort themselves into a little colony where space allows is often the best way to proceed. However, don’t try this in smaller aquaria unless you’re 100% confident that the specimens will tolerate one another’s presence. If in doubt, keep jawfish singly. Breeding can occur in the burrow of either sex, or sometimes in a halfway house built by the male for the purpose. Successful spawning results in a mass of fertilised eggs that are incubated in the mouth of the male. Different species have varying brood sizes, but many consist of hundreds of eggs that must be regularly ventilated by the male. In the case of the yellowhead jawfish, he will partially spit out the eggs and take them back into his mouth. Male mouth-brooding is seen in other marine aquarium fish, notably the Cardinalfish (Apogonidae). The male invests in the brood, limiting the number of his offspring annually, and sticking with the eggs from one female at a time – some species are practically monogamous. This way, he can guarantee that the brood he is incubating is actually his. Among the jawfish you'll find everything from the affordable to the exclusive. I've a feeling jawfish are still to have their day and, as the aquatics world expands its collective knowledge, they'll likely be shown to have even more to offer. To fully appreciate them we must be able to tolerate their relentless re-aquascaping of the substrate and their potential to bury corals or strip the aquarium base of sand and gravel. Are Jawfish so great we're prepared to turn a blind eye to such antisocial shenanigans? Only you can decide…

ALAMY

In their natural environments jawfish reside in burrows that they excavate and tend to themselves

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CICHLIDS Pelvicachromis subocellatus

f o l Jewe

Africa

ALL PHOTOS: RADEK BEDNARCZUK

While not as well known as its Kribensis cousins, this stunning little fish is the perfect dwarf cichlid for beginners.

RADEK BEDNARCZUK A pharmacist by trade, Radek has been keeping fish since he was seven and has a legacy of breeding successes.

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P. subocellatus mix well with other dwarf cichlids that like similar conditions. Companion fish will help to reduce timidity.

Low demand, high reward – what’s not to love? WWW.PRACTICALFISHKEEPING.CO.UK 93

CICHLIDS Pelvicachromis subocellatus

I

T’S A safe bet that you’ve all seen Pelvicachromis pulcher, the Rainbow kribensis. I might even venture the suggestion that it’s the iconic, signature species of dwarf cichlid, probably on par with the German ram, Mikrogeophagus ramirezi. However, there’s another member of the Pelvicachromis genus that’s gentler and more hardy than the better-known Krib, and it’s rather surprising that it’s not more popular and better-known than the ubiquitous Rainbow. Pelvicachromis subocellatus, sometimes called the Ocellated kribensis, inhabits slow-flowing streams and still waters. It’s colourful, doesn’t exceed 10cm in length and is easy to keep. It’s also easy to breed, and while there are many colour morphs of this species, to preserve line purity they shouldn’t be cross-bred. P. subocellatus is distributed in West Africa from Gabon To encourage spawning, to Congo, with some breeders recommend the particularly cooling the water down attractive and adding salt (a ‘Moulondo’ variety teaspoon to 10 hailing from the Moulondo region litres). of Gabon.

Fry are well camouflaged.

Ideal home The species grows to a maximum size of 8-10cm, so your tank doesn’t need to be tall, but it should be relatively long, with a large footprint. For an adult pair, the aquarium should be at least 60-80cm long, 30cm wide and 30cm tall. The bottom of the tank is best covered with fine sand as the species spends most of its day down there, digging in the substrate in search of food. Add a good number of caves in the form of coconut shells, roots, flower pots and lengths of PVC pipe, as well as plants like Java moss, Anubias, Microsorum, and some floating ferns – this cichlid doesn’t like bright lighting. Except when spawning, P. subocellatus is pretty peaceful, and – another bonus – it doesn’t destroy plants. Water current – from a filter or a diffuser, for instance – shouldn’t be 94

PRACTICAL FISHKEEPING

When we see a female looking rotund and very colourful, with a purple spot on her belly, tensing her fins and arching her body repeatedly towards a male, completely lost in the mating dance, it can mean only one thing too brisk. The species likes calm, lazily flowing, well-oxygenated water. The filter should be reasonably efficient, so that metabolite levels remain undetectable. Routine maintenance should include weekly water changes, regular vacuuming of the tank bottom to remove any food remains, and cleaning of the sponges in internal/external filters. P. subocellatus is flexible with regards to physical and chemical

FACTFILE OCELLATED KRIBENSIS 6Scientific name: Pelvicachromis subocellatus 6Pronunciation: Pel-vic-ah-crow-miss sub-oss-ell-ah-tuss 6 Origin: Africa: Nigeria, Gabon, Democratic Republic of the Congo 6 Habitat: Coastal pools and slow-moving streams (some brackish water) 6Size: 8cm 6Tank size: 80x30x30cm 6Water requirements: 6.0-7.5 pH, 5-18°H 6Temperature: 22-26°C 6Cost: In the region of £15 a pair

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The female sees to caring for the fry while the male defends their territory.

conditions. The species does well in both soft and hard water, and will tolerate pH values from 6.0 to 7.5. However, in the long run, they prefer their water soft and slightly acidic. It’s best to use natural acidification methods, such as Catappa, beech or oak leaves. As for feeding, vegetable foods should predominate. The length of this fish’s intestines far exceeds that of its body, so the fewer animal foods in the diet, the less the likelihood of intestinal complaints. For this reason, offer lots of plant fibre and Spirulina, with only occassional shrimp mix, glassworms, Krill and black mosquito larvae. They can also be given dry foods, particularly granulated types that fall to the bottom, as they love to dig in the substrate in search of periphyton.

Coconut shells make ideal shelters.

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CICHLIDS Pelvicachromis subocellatus

Purple passion Adult male P. subocellatus are bigger than the females, and the species is monogamous. When we buy a group of fish, there’s a good chance a natural pair will emerge – all we need to do then is to wait patiently for the spawning. When we see a female looking rotund (as if she were about to burst), and very colourful, with a purple spot on her belly, tensing her fins and arching her body repeatedly towards a male, completely lost in

the mating dance, it can mean only produce up to 200 grains) will be one thing – eggs will be laid very laid on the cave ceiling. soon in one of the tank’s hiding Some breeders use a simple trick places, such as a coconut shell or to encourage spawning by flower pot. An extended replicating natural behaviours – ovipositor is another indicator they half fill a coconut shell that spawning will occur soon. with sand, or push it deep into When it comes to spawning, the substrate. The female will So, there’ll come a day when the female plays the leading then dig out the sand, just as you can’t see the female. Don’t worry, she’ll most likely she would do in the wild. role – she is the one be ensconced in one of the While the female is in the to initiate it. caves, guarding her eggs. hideout with her eggs, the male Anything from a few dozen to a fiercely guards the territory. He’ll hundred eggs (though some females become very aggressive, so it’s a good idea to remove the rest of the fish from the tank, or separate the The larvae feed from pair from the others with a pane of their yolk sacs for the glass or acrylic. first few days. Some people do leave two mated pairs in a tank, with caves for each at opposite ends of the aquarium. If any aggression or territorial battles are seen, the aquarium can then be divided.

Krib kindergarten After a few days, depending on the temperature, the young hatch. Usually they are then moved in the mouth to pre-dug pits in the substrate, though in my tank, they remained in the coconut until the resorption of the yolk sac. After about a week, the yolk sacs will be resorbed and you then need to start feeding the young. Freshly hatched Artemia, microworms, grindal worms and all kinds of foods for egg-layer fry will be readily taken. An amicable pair take care of their young in turns, leading the cloud of fry to various spots in the tank (so-called ‘canteens) where they’ll discover meals of detritus and algae on decaying leaves and so on. These fish can be fascinating to watch as the parents communicate with their offspring by opening and closing their pelvic fins, and vibrating the whole body. In the face of potential danger, following a signal from the parent, the fry fall motionless to the bottom of the tank, playing dead. Sometimes, however, squabbles

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PRACTICAL FISHKEEPING

Both parents will be defensive, even towards each other.

We Recommend...

Tankmates

When breeding it’s best to avoid other tankmates, but normally P. subocellatus are quite welcoming. Many tetras, rasboras, catfish and barbs mix well. You could stick to West African species with either the One-lined characin, Nannaethiops unitaeniatus, or Phenacogrammus interruptus, the Congo tetra.

ALAMY

break out between the pair, leading influence the sex of these fish, to losses among the fry. In such which is determined during the first cases, the young may be left with few weeks of life. If you want the only one parent, usually the sex ratio to be roughly even, the female, or the whole batch may optimal pH is 7.0 and the need to be raised artificially. temperature about 24°C. Do remember that With lower pH values during the first few and higher spawnings, temperatures there If a pair looks reluctant disagreements will be more to spawn, try giving them between the females among live foods such as black young couple, the offspring; resulting in the fry higer pH and mosquito larvae and being eaten, are quite lower temperatures glassworm. likely – they are will lead to a practising at being parents, preponderance of males. so don’t worry too much about If you love small, colourful it. Usually, after a few failed dwarf cichlids, this species is sure attempts, they’ll get it right. After to take your fancy. They are ideal four to six months, the new little fish to help you learn about generation themselves are ready cichlid keeping, being relatively to procreate. tolerant of water conditions, easy to Interestingly, water parameters keep – and, best of all, beautiful.

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FRESHWATER Goby cichlids

La

‘

i

With their strange swimming movements and fascinating shared parenting behaviour, make space in your tank for the cute goby cichlids of Lake Tanganyika.

AD KONINGS Ad is an author, photographer and ichthyologist who is widely regarded for his work with African cichlids.

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Environment Goby cichlids are adapted to the turbulent water of the surge habitat of Lake Tanganyika to such an

extent that this is the only place you can find them. They’re distinguished from other cichlids by their anatomy, as well as their feeding and breeding behaviour. All members of the group have a similar anatomy: a short, laterally compressed body with a remarkably long dorsal fin. To prevent them from being swept away by the surge, their swim bladders are reduced to such an extent that they’re unable to keep the fish buoyant. When they rest on the substrate – while not swimming – their pectoral and pelvic fins are used to secure them in position between rocks, and it’s

common to see the hind parts of their bodies swaying in the current, while their heads stay relatively still in the sometimes vigorously moving water. In the lake, goby cichlids occur in pure rocky habitats, rarely occurring in shallow areas with sand, so if you want to duplicate their natural habitat as closely as you can, the aquarium should contain a fair number of rocks. If possible, these should be piled up close to the top in some part in the tank, as in aquaria, goby cichlids are normally found in the middle and upper parts of the rockwork.

Above: Eretmodus cyanostictus ‘Mpimbwe orange dorsal’.

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NEIL HEPWORTH

A

SMALL GROUP of Tanganyika cichlids is often referred to as the goby cichlids. There are five species described and none grows larger than about 9cm. The most common species are Eretmodus cyanostictus, E. marksmithi and Tanganicodus irsacae – the latter rarely grows bigger than about 7cm.

FRESHWATER Goby cichlids

Adaptations

If you frequently notice the fish are around the filter outlet, it probably means there’s not enough oxygen in the water. Excellent surface turbulence can be provided with airstones and/or power heads. Most goby cichlids are monogamous and live in relatively small areas of about 2m diameter. In captivity they are best kept as pairs and the only way to tell the sexes apart with certainty is to check the vents. Adult females are smaller than males, which is obvious in Eretmodus, but less so in Tanganicodus. For a single pair, you need at least a 100 l tank. Suitable tankmates include cichlids like Simochromis and Tropheus sp.

AD KONINGS

species that makes them so popular. There’s no need to duplicate this The dorsal fin of the goby cichlids is turbulent water in an aquarium long compared to that of other however. While goby cichlids can Tanganyika cichlids and consists of handle a strong surge, they up to 25 spines. Generally, cichlids probably prefer to expend less use the soft-rayed rear part of energy in calmer waters. the fin to fine-tune their position What they do need, though, in the water column, but with A surge habitat is the ‘wave goby cichlids, any movement zone’ of a giant lake, where is oxygen-rich water. Most of the time, the gobies rest on the of it will push the fish nearer waves crash on the shore, substrate, so they actively need the substrate. This, of course, is much like at the to pump fresh water over their just what they need in turbulent seaside. gills. Fish that constantly swim can water. The drawback is that when breathe more easily as they only they want to move from one place need to open their mouth to allow to another, they can only hop or the water to flow over the gills. energetically beat their pectoral fins. So an excellent aeration system is This odd swimming behaviour is essential in a goby cichlid aquarium. just one of the peculiarities of these

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FACTFILE STRIPED GOBY CICHLID

Diet The various goby cichlids have different feeding specialisations, although all species feed on aufwuchs – the layer of algae and micro-organisms covering the rocks and rubble of their environment. Insects and their larvae, small invertebrates, and mites find refuge in this algal mat, and provide food for Tanganicodus irsacae. The two Eretmodus species, E. cyanostictus and E. marksmithi, are pure herbivores while the Spathodus

ABOVE: E. marksmithi, ‘Kigoma’ Tanzania. LEFT: E. cyanostictus, ‘Kasanga’ Tanzania. grazzing.

FACTFILE STRIPED GOBY CICHLID 6Scientific name: Eretmodus cyanostictus 6Pronunciation: Eret-mo-dus sigh-an-oh-stick-tus 6Origin: Africa: Endemic to the southern part of Lake Tanganyika 6Size: Males 8cm 6Tank size: 100x30x35cm for a pair 6Water requirements: Hardwater: 8.0-9.0 pH, 12-25°H 6Temperature: 24-28°C 6Feeding: Herbivore pellets, spirulina flakes, blanched spinach, occasional frozen foods 6Cost: In the region of £15-£20 each

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100 l+

species, S. erythrodon and S. marlieri, appear to be omnivores. As is the case in so many other Tanganyika herbivores, it’s the blue-green algae (cyanobacteria) they’re after. Eretmodus are unique among Tanganyika cichlids by having a set of chisel-shaped teeth that they use to scrape off algae from the rocky substrate. All other Tanganyika herbivores either comb or pull algae. In captivity it’s recommended to feed goby cichlids Spirulina flake food or other types of food with a high vegetable matter content. Planktonic crustaceans such as Cyclops and Mysis are suitable to feed too, but Artemia and other soft-structured food shouldn’t be given as they may upset the digestive system. Algae growing on the aquarium rocks provide supplementary food, and their growth can be encouraged by placing a strong light directly over the rocks that are near the surface. Goby cichlids will reward such effort by showing their best colours and spawning frequently.

80 l+

Propagation Spawning takes place on a horizontal or slightly slanting rocky surface. Egg laying is preceded by the male moving over the spawning site and assuming a head-up and slanting posture while quivering his anal fin, probably simultaneously releasing his sperm. The female then nuzzles the male’s vibrating anal fin, after which she assumes a head-up position and quivers her anal fin in turn. And now it’s the male that nuzzles the female’s ventral region. After a few of these pre-spawning rounds, the female, assuming the same head-up and slanting position as before, releases an egg, which she quickly picks up in her mouth. After each egg has been laid and collected, the male assumes the head-up, fin-quivering position, and the female then nuzzles his anal fin, collecting milt. The eggs are therefore fertilised inside the female’s mouth, although some of them may already have been fertilised as soon as they were laid and touched the substrate. WWW.PRACTICALFISHKEEPING.CO.UK 101

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6Scientific name: Eretmodus marksmithi 6Pronunciation: Eret-mo-dus mark-smith-eye 6 Origin: Africa: Endemic to the northern two thirds of Lake Tanganyika 6Size: Males 5cm 6Tank size: 90x30x30cm for a pair. 6 Water requirements: Hardwater: 8.0-9.0 pH, 12-25°H 6Temperature: 24-28°C 6 Feeding: Herbivore pellets, spirulina flakes, blanched spinach, occasional frozen foods 6Cost: In the region of £15-£20 each

FRESHWATER Goby cichlids

FACTFILE SPOTFIN GOBY CICHLID 6Scientific name: Tanganicodus irascae 6Pronunciation: Tang-an-ee-co-dus ear-rass-say 6Origin: Endemic to the northern part of lake Tanganyika 6Size: 7cm 6Tank size: 100x30x35cm for a pair 6Water requirements: Hardwater: 8.0-9.0 pH, 12-25°H 6Temperature: 24-28°C 6Cost: £15-£20 each

100 l+

ABOVE: T. irsacae, Spotfin goby cichlid. RIGHT: Pebbles in extreme shallow water in Lake Tanganika.

The female starts shaking her head and releases one youngster at a time to be carefully taken up by the male. The male is well aware of what is going on, and waits impatiently with his mouth half open 102 PRACTICAL FISHKEEPING

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after spawning. When you want to grow the fry in a separate aquarium, you could catch the male, once he’s holding the larvae, and place him in a nursery tank. Alternatively, you could leave the mouthbrooding male with the female and try to have a more natural way of reproduction by creating an area in the upper 5-10cm of the water column that’s flat and decorated with small rocks and pebbles. This will be the nursery area where the males will eventually release their free-swimming fry. To build up to such a shallow nursery, you could use imitation rocks instead of real ones, or you could make one with a piece of glass about 15-30cm long and 12-15cm wide – glue this inside a fake rock or out of sight against the rear glass of the tank. Fill the little platform with small rocks (nothing larger than 10cm across) and sprinkle with a thin layer of sand to prevent the fish from ‘arguing’ with their reflection. When lights are placed directly over the small stones on the platform, a lush algal vegetation will grow to welcome the newborn gobies.

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Tanganicodus produce about 20 eggs per clutch, Eretmodus about 35. The female broods the eggs and young for the first 10 to 14 days until the young are around 8-10mm, but all the time the male stays close by her side. At the end of this period, the female tries to get her partner’s attention once more, signalling her readiness to transfer the young, days before the male finally takes them. At first it looks as if the pair are going to spawn again, with both male and female active in chasing away intruders. Once they’ve secured their ‘swapping site’, the exchange of young begins. The female starts shaking her head and releases one youngster at a time to be carefully taken up by the male. The male is well aware of what is going on, and waits impatiently with his mouth half open. Sometimes it looks as if he’s begging the female for another youngster, and almost picking them out of her mouth! After all the young have been transferred to the male’s mouth, he broods them for seven to eight days. The male and female stay close together during the entire brooding period, and a mouthbrooding parent does not eat. The fry are normally released in extremely shallow water among pebbles. While you can breed gobies in a special breeding tank, the simplest way is just to leave them with other cichlids in a community aquarium. When a male and female have been introduced into the tank, they normally form a pair and stay together most of the time, including when they are not breeding. Mouthbrooding females are easily recognised by their swollen buccal pouch. Never remove a mouthbrooding female from the tank because the larvae will be transferred to the male two weeks

Another name for the goby cichlids is ‘Tanganyika clowns’.

Tanganicodus have smaller, thinner mouths.

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AD KONINGS

Eretmodus marksmithi ‘Mzungu’.

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ADVERTISING FEATURE

As eSHa celebrates its half century, it reveals how it’s stayed true to its core aim of making high-quality health care products for aquarists. T’S A FAMILIAR story – a keen tropical fishkeeper sees an untapped potential and goes on to develop a product that achieves worldwide acclaim. eSHa’s story is much like this, and it all began with its Dutch founder, John de Cocq. Over the past 50 years, he and his son Marc de Cocq have transformed eSHa into an international business operating in more than 25 countries.

John de Cocq studies ichthyology before setting up his own aquatics shop, Sea Horse. Unimpressed by the efficacy of the aquatic remedies then on the market, he begins doing his own research with help from a friendly pharmacist. John launches eSHa (the ‘SH’ after his shop Sea Horse), in Maastricht, Netherlands. eSHa was officially registered in the Chamber of Commerce in 1968, making it 50 years old this year. Development begins with the production of a landmark product – today known as eSHa 2000 – that treats fungi, bacteria, fin rot and more. Thanks to its popularity, more products are added to the range, eliminating more specialised diseases. As word spreads, demand grows and eSHa evolves into a wholesaler and production company. It branches out into making glass aquariums, importing accessories from the Far East, and sets up a plastic blow-mould facility for aquarium filters and other products in Maastricht. 104 PRACTICAL FISHKEEPING

across Europe. eSHa responds, investing in more manufacturing facilities and increased mechanisation. eSHa introduces a world-first: the five-in-one eSHa Aqua Quick Test, an easy-to-use dip test measuring nitrate, nitrite, GH, KH and pH. The latest version is a six-in-one test, which adds chlorine to the list.

A decision is made to take eSHa back to its roots and focus on what it does best. eSHa rationalises its product portfolio, and sells its wholesale operations, print shop and aquarium and accessories manufacturing facilities. All attention turns to research, consultancy, medicine production and more. Regulations over medicines are tightened across Europe, which sees a major shake-up in the industry. The Dutch government is one of the first to implement the new EU laws, using the big pharmaceutical companies as a template. As a result, more than three-quarters of Dutch veterinary medicine producers and manufacturers cease production. Nikki Boumans, head of UK sales and marketing, says: “We were lucky to stay in business, but had to build a new manufacturing site and install new quality control labs. However, this meant we were able to improve our products and ensure quality research laboratories.” The aquarium and pond markets experience strong growth in the UK and

Since the launch of its first product, eSHa 2000, the company has been at the forefront of research into highly effective medicines, supplements and testing kits for the aquatic hobby.

The Dutch Ministry of Health and Ministry of Agriculture make it mandatory for manufacturers to hold manufacturing licences for the production of medicines for fish. Today eSHa employs 18 staff members across its 1,800m2 production facility and has two warehouses. Although John died in 2009, eSHa is still family owned. Research and production is solely concerned with health care products and supplements for ornamental fish, products to combat aquatic snails and algae, aquatic plant supplements, and water test strips. The company will no longer venture into other fields, “simply because we believe in specialising in what we do best,” says Nikki. Research and new product development is ongoing, and the UK will soon have access to 18 products. The latest, eSHa alx, has been formulated to combat parasitic crustaceans and can be used in freshwater and marine aquariums.

Find out more at eshalabs.eu

eSHa 50 YEARS:

Est.

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THE SOLUTION FOR RELIABLE AQUARIUM PRODUCTS

TH

eSHa OPTIMA

Algae

Vitamines

Crustaceans

Nematodes

UK/USA: Pl miner ant extracts (400m healthy wa als and trace element g), vitamins, increases reter. Builds up the immus for natural, colour sple sistance against dise ne system, il ness. Reandour. Speeds up a fuase, itness and freshwaterd lealet before use. Apl recovery from children andaquariums. Keep out plication in place and i pets. Store frost-freof reach of n original pac e in a cool, kaging. dark GR: Φυτικά βιταμίνες, μέεκχυλίσματα (400mg) φυσικό και ταλλα και ιχνοσ , ανοσοποιη υγιεινό νερό. Αναπτύ τοιχεία για Για ταχύτερτικό, έντονα και φυσι σσει το Διαβάστε τ η ανάρρωση απο ασθέκά χρώματα. Για χρήση σεο φυλλάδιο πριν τη χρήνειες. Κρατήστε τ ενυδρεία γλυκού νε ση. εκτός ψυγεο μακριά από παιδιά. ρού. ίου μόνο στ Διατηρήστ η συσκευασ ε το ία του. HU: Növényi vitami kivonatok (400 rmészetes ésnok, asványi anyagok,mg), nyo tja az immuegészséges vizet bizt melemek ét és egész nrendszert, kondícióosítanak. s t gségek kezégét. Gyorsítja te je és a halak s a át a haselése után. Az a lkácósfe ép lést vízi halak. Védználati utasítá tAjánl eőt gtől. Az üve je fagytól, fén t l ot az lja eredeti c get és a hasz ála i u és somagolás ta íá t ban.

FISH HEALTH BOOSTER Water conditioner for ornamental ishes in freshwater aquaria.

Healthy water for healthy ish Gezond water voor gezonde vissen Gesundes Wasser für Gesunde Fische De l'eau saine pour un poisson en bonne santé

eSHa OPTIMA is a unique combination of the essential components found in tropical rivers, lakes and streams. These components are blended with trace elements, minerals, vitamins and natural growth enhancers to give your ish what they are accustomed to in their natural environment.

AGAINST SKIN FLUKES, GILL FLUKES AND TAPEWORMS

eSHa gdex®

Veterinary medicine for ornamental ishes in freshwater and marine aquaria.

Freshwater turtles

Goldish

eSHa gdex® treats skin lukes, gill lukes (Monogenea like Gyrodactylus and Dactylogyrus) and tapeworms (Cestodes). It can be used with all our other freshwater medicines for an extremely broad range of action. eSHa gdex® does not colour the water and it will not lead to a bacterial bloom.

eSHa HEXAMITA Plants

Red leaf plants

Coral

Marine ish

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Testkit

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Veterinary medicine for ornamental ishes in freshwater aquaria. eSHa HEXAMITA is a unique treatment that combats diseases in Discus and other Cichlids like ‘Hole in the head disease’, fungal and bacterial infections. It will prevent diseases in newly acquired stock and will protect the ish from secondary infections. eSHa HEXAMITA can be used in combination with eSHa EXIT and / or eSHa gdex. eSHa 2000®’s wide range action treats over 18 symptoms and disease organisms. It treats many fungal, bacterial and parasitic infections, helps heal wounds and protects the skin layer.

50 x 6 300 Tests

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eSHa EXIT treats all kinds of ‘Spot’ (Ichthyophthirius multiiliis), it also cures Velvet. It is safe to use with sensitive tropical ish.

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November 21st 2018

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6 The weird world of ‘electric’ fish

6 How to house Panaque catfish

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6 Attractive Tiger barb alternatives

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6 Set-up for Oscura heterospila

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6The latest Aquatic News 6Fishkeeping Answers 6Ethical Debate 6New gear reviewed

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SHOPS & EQUIPMENT

GEAR

FIRST LOOK

Want to know how the goods on sale really perform? We put them through their paces so you can sort the good from the bad... They aren’t cheap, they aren’t easy to set up and are risky when set up wrong, but C02 really helps plant growth.

108 PRACTICAL FISHKEEPING

COLOMBO CO2 PROFI SET AND SOLENOID Price: Sold separately – CO2 Profi Set sells for between £150-£200, Solenoid around £65 More info: www.colombo.nl Reviewer: Nathan Hill In a market that was for a long while saturated with expensive entry level CO2 diffusers, many of us lost confidence in the idea of affordable carbon for the aquascaping hobbyist. Some of us took the risky high road of using CO2 fire extinguishers to make things economical, willing to offset the chance of a regulator failure against forking out astronomical prices for aquariumdesignated cylinders of gas. Others persevered with off-the-shelf designs and rapidly realised how costly it became. This Colombo offering sits somewhere in the middle. It’s pretty pricey, but arguably much safer than a fire extinguisher. To its benefit, it has a cylinder that holds 800g of carbon dioxide – many of its nano rivals have cartridges (too small to even call them a cylinder) as little as 20g. You can assess the efficiency of that for yourself. For 20g cartridges you’ll pay out somewhere between £10 and £18 for three of them – 60g total. A refill for the 800g Colombo set comes in around £40. But then again, I typically pay around £25 for 2kg of CO2 in a refurbished fire extinguisher. 800g will supply me enough gas for about two or three weeks at best in a 60x30x45cm aquascape, assuming I’m not gassing heavily. The regulator itself is weighty, sturdy and has a smooth enough action. With CO2 dosing you want really fine tuning abilities, and

this has it. Whether you want one bubble of gas ev second, second-and-a-half or two seconds, you can it with accuracy. It connects directly to the top of t cylinder through a thread action, and as long as yo keep the threads absolutely clean (I’d frequently go over my regulator/cylinder threads with a cotton bu and some silicone lubricant), then you won’t exper gas leakage. If it’s the first time you’ve ever connec regulator to a cylinder, I’d advise being quick, othe little blast of released gas can give you a sudden ‘h Also in the package you get a length of CO2 resist and a bubble counter/diffuser. Depending on how ha is, that tubing will eventually turn a chalky white a so I suggest replacing it every few months (but if yo aquascaper obsessed with everything looking fresh do that anyway). The bubble counter and diffuser p the tank easily enough, held in place with a sucker couple of spares as this will turn chalky after a whi opening it up to clean it just involves unscrewing t getting inside. Look closely and you’ll see a little sp g as well. That’s the non-return valve that means if you ever run out of gas, the water won’t start syphoning back out of the tank. That’s the whole package. I won’t lie, it doesn’t seem ‘that’ great value, especially if paying near the £200 kit price. With £40 for the cylinder, that means I’m paying out £160 for a regulator, some silicone airline and a bubble counter. I don’t even get any cheap clamps and suckers to tidy up the airline. You can build on the kit by adding a separately sold solenoid. When plugged into a timed socket (around £3 upwards from electrical and homeware stores), this allows total on/off control of your gas supply. The usual ‘scaper trick is to turn the gas on an hour before the lights come on, and have it lead by an hour when the lights go off again. This avoids huge swings of pH, as well as wasted CO2 (since plants don’t use it at night). My worry is that the solenoid is in-line. I’ve tried to butcher something like this together in the past on a pressurised CO2 unit, and all that happened was that the hose exploded in the night. Perhaps I was using substandard hose – or perhaps Colombo knows something that I don’t. Either way we couldn’t put it to the test as the solenoid didn’t work when we plugged it in, and we’ve given up on waiting for the replacement to come through.

VERDICT If you’ve got the money for the refills and you don’t mind setting the regulator every morning and night, then great. If you want to run it with the solenoid then I can’t really comment. I would expect a LOT more if I was paying the upper end for this. EASE OF USE:  FEATURES:  VALUE:  OVERALL: 

Check valve, airline and diffuser ccincluded

VULTRON AIRPUMP 1500 Price: Around £14 More info: yihufish.com Reviewer: Nathan Hill Have you ever bought a product just because it had a cool name? That’s what happened here. The Vultron 1500 is a pyramid design airpump with a pumping depth up to 36cm, and is the smallest model in a line of five. The 1500 moniker refers to… I’m not really sure. The air flow rate (presumably at zero head) is 110 litres per hour and it will deliver that at the expense of 2W of running power. So it’s nicely economical. This model comes with a single outlet, just under 1m of airline, a non-return valve and funky looking glassmounted (with sucker) air diffuser. I’m loathe to call it a stone, as it’s a plastic device with a foam pad, but it does belt out air all the same.

Is it quiet? Well no, not particularly, but then it’s no louder than similar-sized airpumps either Flow is controlled by a curiously smooth rotating dial on top of the unit which I reckon will be a bit of a headache to use with wet hands. While you can clearly see the port for the air filter underneath the unit, and while it looks like it ought to be easy to access, I’ve not quite worked out how to do that yet. As far as I can see, VERDICT This does the job, and for maintenance will not too bad a price. It’ll be involve removing four interesting to see how much cross-head screws to flow it loses when that filter access the inside. gets clogged though. Is it quiet? Well no, not particularly, but EASE OF USE:  FEATURES:  then it’s no louder VALUE:  than similar-sized OVERALL:  airpumps either.

WWW.PRACTICALFISHKEEPING.CO.UK 109

❯

SHOPS & EQUIPMENT

GEAR

FIRST LOOK

WHAT ARE POLYMER BALLS? These handy spheres are relative newcomers to the pond treatment scene. We talk to three manufacturers about their use.

ALL: STEVE BAKER

When it comes to pond remedies bacteria breaking down elevated and medications, the stock on most ammonia and nitrite levels. shop shelves hasn’t changed much Enzymes break down organic over the last few years, but there’s matter, enabling further breakdown one obvious newcomer – polymer by bacteria, clearing up water balls. They’re produced for both clarity issues and built-up silt. pond and aquarium use, but what Pond balls are mostly suited to exactly are they? And when should boosting the performance of they be used? mature filters and ponds – It was Evolution Aqua’s either in early spring when Pure Pond Balls that the bacteria colony is at were the first of this an all-time low after type of product on the cold winter Don’t like the idea of a spent the market. temperatures; They introduced when introducing polymer ball bobbing about? Put it the idea of more livestock, in a filter bag and hang it in polymer for which increases your filter so it can be containing bacteria the bioload; after a easily removed. and enzymes, but now deep clean of the pond; the larger polymer ‘bombs’ or when you are suffering are the more popular option. with water clarity issues. The idea? Just drop the ball in Many pond keepers use them your filter or directly into your pond to kickstart new set-ups, and and sit back while thousands of although they will speed up the little monsters escape the polymer maturation period, there are and get straight to work. Simple. products out there more suited to The mixture of bacteria and starting a new system, such as enzymes deal with cases of poor Evolution Aqua’s pure+ filter start water quality, with nitrifying gel and Cloverleaf’s Bio Gel.

110 PRACTICAL FISHKEEPING

What is polymer?

BELOW: For ideal usage, put the polymer ball in a small filter bag and pour any liquid into the pond.

It’s a very loose term; the word literally means ‘many parts’ and it’s used to denote any substance that’s made up mostly (or completely) of similar (repeating) molecules (monomers). DNA, cellulose and muscle proteins are all natural polymers, though most of us would think of synthetic plastics like polyethylene and PVC (poly vinyl chloride) when the word comes up. So what type of polymers are used for pond remedies? We don’t know. The companies understandably don’t want to reveal their secrets, but we did ask the manufacturers if any residue (plastic or otherwise) was left over from their product.

AQUA SOURCE BALANCE SPHERE First look: Steve Baker Prices: £14.95 More info: aquasourceuk.co.uk Is there any purpose to the fluid in the tub? Aqua Source says: “The liquid inside the tub is a part of the manufacturing process, and contains a small food source for the bacteria to survive, as do the balls themselves. Some bacteria and enzymes migrate from the spheres, which is why you must put all of the contents into the pond. This is how the product can have a shelf life of two years. “As with all bacteria, if it doesn’t have a food source, then it will die, so after treating the pond or aquarium with Aqua Balance Balls & Sphere, most of the bacteria will die off if the food source is not sustained. Effectively, it will do its job of reducing ammonia and nitrite, but the effectiveness and longevity depends on other factors.” And enzymes? “The spheres also contain enzymes that will also get damaged and die off, which is normal. These specific enzymes chomp on the organic

Treats: Up to 30,000 l matter in the water, giving clearer water.” Is there any lingering residue of the bomb left once the bacteria is spent? “There’s no lasting residue from the balls once exhausted.” Is there any concern of an allergic reaction? “We’re not aware of any allergies to humans, although we do advise that people do not eat our balls! If swallowed, they would lead to a dodgy tummy. The bacteria is harmless to humans apart from that.” Aqua Source has also adopted polymer balls as a way of delivering other pond additives including Aqua Balance Enzyme for promoting fish health and recovery, Blanketweed Resolve, and a fish treatment called Remedy.

EVOLUTION AQUA PURE POND BOMB First look: Steve Baker RRP: £14.95 More info: evolutionaqua.com Is there any purpose to the fluid in the tub? Evolution Aqua says: “It’s classed as an activator gel, but it also aids shelf life and transportation.” Is there any lingering residue of the bomb left once the bacteria is spent? “Yes, the bacteria, enzymes and a food source lie dormant inside the ball when the product is on the shelf for up to two years. The bacteria have everything they need inside the ball to stay alive and intact until they are needed. “Once placed into an aquarium or pond, the bacteria are enticed to leave the ball to feed on nitrogenous waste. This can be seen by the ball shrinking and breaking up. If you place the bomb into a glass of RO water, with no flow or nitrogenous load, the ball stays the same size and intact. If you place it in an aquarium or pond with load and water flow, the bacteria leave, and the ball shrinks. Our ‘ball’ is actually a net, only allowing certainsize bacteria in and out. “A spent ball can be left in the pond where it will actually act as a substrate media for bacteria if no better biological filter media is

Treats: Up to 20,000 l available. But if you have a decent filter, and don’t like the look of a spent ball, remove it.” How do the enzymes and bacteria work together? “The enzymes themselves don’t consume waste, but they can convert waste into other waste, which bacteria can then use. “Enzymes are very important, and we talk as much about enzymes here as we do about bacteria themselves.” Is there any concern of an allergic reaction? “I’ve never heard of one and I’ve seen a few million bombs get manufactured, sent out, and used all over the world, but I guess it’s possible to be allergic to virtually anything. Some people are allergic to prawn shells, bloodworm or synthetic sea salt.”

Treats: Up to 60,000 l

CLOVERLEAF ABSOLUTE PEARLS First look: Steve Baker RRP: 15.99 More info: cloverleaf.uk.net You don’t use a fluid to carry the pearls like other manufacturers do, is there any reason for this? Cloverleaf says: “With all due respect, we do use a ‘fluid’. Unlike other manufacturers of most filtration aids, we use living cultures of various nitrifying organisms – archaea, anaerobic and aerobic bacteria, plus the enzymes these organisms naturally produce (together with a few nitrifying fungal and yeast organisms), as the ‘fluidic soup’ that is absorbed by each of our Cloverleaf Absolute Pearls. “In fact, due to temperature and particular atmospheric conditions in our retailers, you will sometimes find a small residue of this bacterial soup in some packets of our pearls.” Is there any residue when the pearls are fully exhausted? “Absolute Pearls are made of a selection of natural organic polymers that will either be eventually fully digested by the micro-organisms in the particular aquatic environment, or shrink to a pea-like ball. In time, this will itself be absorbed by various micro-organisms.” Does the user need to be careful with this product – can there be any allergic reaction at all? “We do advise on each packet: ‘Wash hands after use. Keep in a safe place out of reach of children’. “This is only sensible, but no, Absolute Pearls only carry the micro-organisms that you would normally find in a healthy and well-maintained pond filter.”

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OPINION

NATHAN HILL When it comes to public aquaria, tight budgets and old equipment is a challenge. But are they giving out such a negative message that they become their own worst enemies?

I

’VE BEEN entertaining this month. A close friend of mine came across to the UK to visit, and so I took on the traditional English role of tour guide. Given that this friend is deeply immersed in the aquatic world, and given that we were in the same city as a renowned public aquarium, it was inevitable that after introducing her to such British delights as fish and chips, we should saunter on in and take a look.

Bracing myself Now here’s a thing. I used to work in public aquaria. I was aquarist at a Sea Life centre for a few years in the mid-90s. My memories of that place involve low-tech gear and shoestring budgets, and while the displays we had weren’t exactly cutting edge, they were at least relatively well matched to the calibre of home displays of that time – just a lot bigger. Fast forward two decades, and it looks

Nathan Hill is Practical Fishkeeping magazine’s associate editor, biotope fancier, aquascape dabbler and part-time amateur skateboarder.

Changing the world

like while the home hobby has evolved in a huge way, public aquaria are still using the same tired equipment that was already borderline obsolete at its first use. This was my first time entering a public aquarium as a paying customer for as long as I can remember. Since leaving Sea Life, and because of the contacts I have, if I ever want to visit one I can usually send out a couple of grovelling emails and get a gratis ticket. This time I wanted to pay. So I did. Then I instantly regretted it when the price came up. At £18 a head, I expect guides to do somersaults on request and follow me around wafting me with a huge banana leaf and feeding me grapes. The displays themselves were trying to make the best of a bad situation. It appears that since I left that side of the industry, nobody has yet worked out how to stop condensation forming on cold glass. It’s just that these days they don’t bother to wipe it off. Every time I pressed close to an exhibit, I risked soaking myself.

NATHAN HILL

Ashamed yet, human?

Guess the fish answer from page 39: Red tailed catfish, Phractocephalus hemioliopterus.

114 PRACTICAL FISHKEEPING

The other thing that leapt out at me was how downbeat the information was. I’ve noticed this at a few public aquaria, and I’ve no idea why the folks in charge of the displays think we all want to be told what total scumbags humans are – I’ve seen a couple of museums do this as well. I’ll be enjoying myself watching a shark in a tank right up until the microphone scornfully announces that humans kill over 100 million sharks annually. Thanks for that. In fact, many public aquaria are now more like shrines of death and destruction than they are celebrations of aquatic life. From bleaching of corals to discarded plastics, the emphasis of the public aquarium seems to have shifted to two hours of intense guilt-tripping. When I left I had no fond memories, only self loathing. Yet the thing that stuck with me most was the absence of progress. I repeat, the domestic hobby of fishkeeping has moved a long, long way in the last 20 years. Some public aquariums have made great leaps in that time – just look at the work on coral spawning that Jamie Craggs has done at the Horniman museum. Unfortunately, other public aquaria seem to have drifted into becoming foghorns of misanthropy, hellbent on shaming the everyday human. All of this combined makes me wonder if public aquaria, by and large, are going to become just another evolutionary drop out. Ultimately, for a moderate outlay, we are all now capable of putting on a better display tank at home. And more so, we can do it without some heavy guilt trip being laid on us just for existing. Then again, I might just be sulky because the shark tank was closed when we visited.

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