Tabla de contenidos para July 2023 en Practical Fishkeeping

SPECIES SHOWCASE Three-spined sticklebacks WHAT A FABULOUS bundle of genetic confusion the sticklebacks are. As a family, they are somewhat diverse, with at least 16 species across five genera. Of those, one in particular will be familiar to UK aquarists: the threespined stickleback, Gasterosteus aculeatus, dler’ to the British angler. Genetic variation within three-spined sticklebacks is profuse. There are the anadromous versions that live in the sea and return to freshwater to spawn, large (up to 11cm) and silvery fish with protective scutes along their flanks—a testament to the different predation pressures they face from their freshwater kin. But we needn't concern ourselves with those, as they are rarely (if ever) offered to hobbyists. The freshwater three-spines are all descendants of ancient marine sticklebacks. Denied access back to the sea…

SPECIES SHOWCASE Krobia xinguensis SOMETIMES SPEND ages searching for fish I want only to realise after keeping them that they are not for me. In other cases, a fish I never knew I wanted finds its way to me and into my heart. This latter is what happened with the red cheek krobia, Krobia xinguensis. I'd seen pictures of them and they looked nice, but I didn't feel inspired enough to search for them. Then a few months ago a local aquarist friend asked me if I was interested in rehoming his pair as they wouldn't fit into his fast-flowing River Xingu biotope. Within hours another friend approached me saying that he had three adult red cheek krobia looking for new home. As my 120cm display tank needed something as…

I'm thinking of purchasing some sticklebacks for my wildlife pond, which holds around 3,600 litres and contains dragonfly larvae and newts. There is quite a bit of blanketweed in the pond and it also gets frozen over in the winter. Would they be suitable, and if so, what should I feed them? Any advice would be welcome. JEREMY SAYS: I love sticklebacks and kept and bred them in my pond last year. The only problem is that they are prolific breeders and may actually upset the balance of your wildlife pond. I bought five pairs for my otherwise fishless 2,200-litre pond and they spawned and had fry within a few weeks of introducing them. I then put one pair in a wooden barrel water feature, and they bred in there…

[TROPICAL] A couple of months ago I set up a new 120cm, 162-litre shallow tank with an OASE BioMaster Thermal 350 external filter, kept at 23°C. The hardscape is river wood planted with epiphytes, and I have a fine sand substrate covered with a layer of fine gravel, as I found the sand got dirty too quickly. The tank isn't too over-stocked but there are a good number of nano community fish, Sterbai corys, Otocinclus, Amano shrimp, cherry shrimp and Clithon snails. My issue is that the tank looks hazy no matter how many water changes I do. Those I've had in the past always had crystal clear water, so I'm struggling to understand why it won't clear this time. The filter is filled with Seachem Matrix with Purigen and…

FASCINATING FISH Maassi loach IF THERE'S ONE thing that really unites catfish and loach keepers, it's the desire for bland, whiskery fish that hide away. The blander and more secretive, the better. The fish you see here is something of a grail species for the loach hobbyist. At first glance, and to the inexpert eye, it probably looks like some Pangio castaway, minus the attractive orange embellishments. Get closer and you'll see plenty of anomalies on a distinctly unique fish. There's the vast dorsal fin running down the back like some inverted knifefish. There's the long and deeply forked caudal fin, something you'd expect to see more on high-speed pelagic species rather than a bottom dweller. And if you get really close, you might note the absence of the mobile…

HABITAT Western Guiana Shield FACTFILE STRIPED PIKE CHARACIN 💧 Scientific name: Boulengerella lateristriga 💧 Pronunciation: Boo-long-err-ell-ah lat-err-iss-stree-gah 💧 Size: To around 25cm 💧 Origin: Brazil, Venezuela and Colombia 💧 Habitat: Opts for black water streams with vegetation 💧 Tank size: 200×60×60cm 💧 Water requirements: Soft and acidic water; 4.0-7.5pH, 1-8°H 💧 Temperature: 23-28°C 💧 Temperament: Will eat anything that fits into its mouth 💧 Feeding: Not too hard to wean on to dead meaty foods, also takes insects, but largely refuses dry food 💧 Availability and cost: A rarity that's seasonally available from specialist stores, prices from around £30 AS I STAND there, looking at the large inselbergs in the distance, I wonder how mind blowing this area of the Western Guiana Shield must have been to Humboldt, 222 years ago. I…

I'd like to keep a group of red-bellied piranhas. The tank is a Juwel Vision 151×61×64cm holding approximately 450 litres. How many can I keep in a tank of this size and what size should I buy them at? The tank has an internal filter which I'm thinking of leaving in alongside some additional filtration, so would a Fluval FX6 do the job? What's the best decor, as I know these fish can be a bit on the shy side. I only want to feed dead food, so what would you recommend for a balanced diet? NEALE ADVISES: Piranhas are somewhat tricky fish to recommend as pets. On the one hand, they're undoubtedly interesting, attractive in a sinister sort of way, and contrary to popular misconception, will generally eat fresh…

I have a 20-year-old pond with probably 80 assorted small fish, and until now, Elodea has been the main oxygenating plant. I thinned it out last year as it was over most of the surface, but this year, there are only green stems left with nothing around them. On looking at them, they have a diaphanous growth, which looks like liquid hand soap, wrapped all around them. Can you suggest a replacement plant? JEREMY SAYS: My first thought is that the leaves have been damaged by ice or even been exposed at the surface and have dried out, been wind burnt, or again, frozen. My second suspicion would be predation by stagnalis pond snails, which, if there are enough of them, can decimate pond plants. Stagnalis aren't actually plant-safe, whereas…

I was reading recently that blind cave fish are born with eyes, and it made me think that perhaps they'd make a really interesting breeding project. Do you have any tips on howto go about this in terms of tank set-up and rearing the fry please? NEALE SAYS: Yes, oddly enough, the fry of these fish are born with eyes, but they soon degenerate, resulting in the blind fish we are familiar with. As it happens, the blind cave tetra is actually quite a simple fish to breed. Like most tetras, it's an egg-scatterer, and all it really takes is putting a well-fed and sexually mature pair in a tank and letting nature takes it course. But like so many other egg-scatterers, the parents are quite likely to eat the…

I'm in need of some urgent help. I own a lake with carp and the fish for the last month have been getting brown fungus all over them and I've lost seven already with at least another 30 very sick. Can you please advise? PETER ADVISES: From the image, it does indeed look like a fungus infection. As you probably know, fungus infections are normally grey in colour but they become brown or even green due to entrapment within the fungus filaments of brown detritus or green algae, respectively. It it is tungus (such as Saprolegma) then unfortunately there isn't much you can do in a large fishery lake, as chemical medication on such a large scale isn't really feasible. A deteriorating water quality, and/or low water temperatures, can be…

THE QUIRKY ORDER known as the Anabantiformes covers a huge range offish diversity in terms of size, habitat and spawning strategies, with the most familiar members for aquarists being bettas, gouramis and snakeheads. Many other anabantoids—also known as labyrinth fish—are kept by Anabantoid Association of Great Britain members, including Badis, combtails, bush fish, and Pristolepis. The Anabantoid Association of Great Britain (AAGB) is one of the longest running aquarium clubs in the UK, having been formed in 1981. The main goal of the AAGB is to promote the interest in the study and maintenance of anabantoids in home aquaria, as well as being an active contributor to conservation projects, such as the Sandelia Project in Africa's Western Cape. Twice a year the AAGB holds an in-person conference, and the flagship…

MARINE Breeding FIRSTLY, I SHOULD introduce myself. My name's Robin Mannion and I am the founder of Pholium Mariculture UK. After managing the aquarium at a clownfish research project in Tahiti I returned to the UK. I was dismayed to discover how few captive-bred marine fish were available here, and that there wasn't any commercial breeding happening in the UK at all. A shocking 90% of all reef fish for domestic aquaria are wild caught, and I suspect that number is even greater for the UK. Breeding benefits Captive bred fish have many ethical and practical advantages over wild caught—the most obvious one being that taking millions of fish off the reef is simply not sustainable. These issues range from the damage that can be caused to the reef and…

ADVICE Fishkeeping Answers [TROPICAL] Duestion of the Month I'm getting a 1.5m tank, which I'd like to plant up and keep some discus and angelfish in – maybe 5-6 of each. But I've now been told that they don't mix very well. I thought these fish were found together in the Amazon, so I'm confused. Do they work or don't they? If not, what's different about keeping them in an aquarium that means they don't mix? Please can you advise? JEREMY REPLIES: People have been trying to mix angelfish and discus together for half a century, and yes, you are right, they can be found together at some locations along with other large cichlids and even piranha. The problem in the aquarium is that even with tank-bred, domesticated discus, the…

[TROPICAL] We have a 90×45×45cm tank with eight harlequins, eight rummynoses and six corys. We'd very much like to add some tiger barbs but we've heard they need to be kept in large groups or they become spiteful to other fish in the tank. So how many will we need, and do we have enough room in this tank? It has lots of Java fern and bogwood with places to hide. We love these fish but don't want to add them if they're going to stress out the other fish, so we'd value your opinion on this. BOB REPLIES: Tiger barbs do have a somewhat deserved reputation for being ‘nippy’, and as you mention, this behaviour is most likely to manifest itself when they are kept in small numbers. While…

I wonder if you can advise me on the frequency of water changes and how much I should be changing each time, please? BOB SAYS: There are many factors in play when it comes to how often you should carryout a water change, and how much water to change when you do. The size of tank, the stocking level, how messy the fish are, the size of the filters, the amount of plant growth in your tank, and the quality of your tap water can all play a part. However, in simple terms, for most community-type aquariums with average stocking levels, a weekly water change of around 25% of the tank's volume is a good baseline to keep things healthy. It's worth having a basic liquid test kit to check…

TROPICAL Bichirs THE BICHIRS ARE firm favourite for many, and for good reason. Along with the ropefish, they are a social group of armoured, serpentine fishes belonging to the order Polypteriformes, the oldest living ray-finned fishes. There are currently 14 living species ranging in sizes from 35cm to over a metre. Whilst the earliest recognised fossils only go back as far as the Late Jurassic (148mya), paired with genetic tracing, we know these primarily African fishes date back to the early Devonian (384mya). Polypteriform fossils have also been found in South America, meaning this divergence would have occurred before the continents split. To top it off, a fossilised bichir discovered dating back 5.3-11.6mya in Chad, known as Polypterus faraou, is identical to the popular aquarium species Polypterus bichir (including the…