Practical Fishkeeping November 2023

WITH THE sun now truly setting on the year behind us, and the longer winter nights yawning their way into view, I suspect that I'm not the only person out there feeling a little excited. Maybe it's just atmospheric, but there's something about settling down front of a brightly lit aquarium on a cold and dark night, and just losing yourself to fish for hours. With that in mind, I'm hoping this issue provides some ideas and inspiration for fish you might not otherwise consider. Hannah Taylor does sterling work of championing Schismatogobius (as soon as I'd edited the feature I was Googling where to buy some), while Daniel Konn-Vetterlein reminds us of some catfi sh close to my own heart—the dwarfi est of dwarf suckers. And if it gets…

ENVIRONMENTAL CONDITIONS PLAY a huge role in restricting where fish can survive, with water temperatures a major determining factor for the survival of a species. This is because the majority of them are ectothermic, meaning the temperatures of the surrounding environment heavily influence their metabolism, growth, activity and, as fishkeepers are well aware, it can also be a trigger for spawning events. All ectotherms have adapted to the speed of these processes under the temperatures they evolved in, and when moved outside of this range it can drastically impact their ability to function effectively. Similarly, fish are largely constrained to an environment by the forces of diffusion and osmosis. Having evolved to live in equilibrium with certain parameters of water hardness, pH or salinity, a shift away from those parameters…

It never ceases to amaze me how well various fish species are adapted to extreme environments. You can find fishes in freezing arctic waters, in hot springs reaching 40°C or 8000 metres below sea level. Some fish need atmospheric oxygen to live while others can wait months for their next meal. My favourites are the species that adapted to survive without the one element everyone immediately associates with fish: water. Hung out to dry Many killifishes are famously found in regions where dry seasons occur, living fast and dying young, completing their whole life cycle in mere weeks. They need to make the most of the short windows of opportunity between the dry seasons to ensure their species’ survival. When the rain arrives and the ditches are filled up with…

PROBABLY MY BIGGEST hang up with aquaria is how still they are. As someone who jumps in every stream I find, I'm fascinated with the ebb and flow of water, and I lament that so few tanks in the UK are set up to replicate laminar movement. As such, I offer the following catfish with a proviso. If you're going to seek some out, give them a home that feels like the real deal, and I will salute you. Assuming I don't do it first. The catfish you see here is a marvel of compaction and river dwelling. Pseudolaguvia shawi, a rare treat that might occur under the name of bee catfish if it pops up in a specialist store, is tiny and well adapted. Officially reaching just 3.8cm (though…

TEMPERATE Fancy goldfish RECENTLY I LEARNED that Pets At Home has removed goldfish and fancy goldfish from sale, with one customer telling me the reason was that they “were too messy.” Those who want ‘coldwater’ fish in unheated aquaria can still buy temperate species like zebra danios and White Cloud Mountain minnows, and even feed them now with Tetra Temperate Flake food. Small, hardy species like those are better in many ways for smaller unheated aquaria, but where does that leave the world's longest domesticated fish? And is it a good or a bad thing that they are now available in 400 fewer aquatic stores than before? I've specialised in many areas of aquatics throughout my life from cichlids and plants, to oddballs, koi and marine, but goldfish have always…

LIMIA NIGROFASCIATA OR the humpbacked limia, are unique and unusual looking livebearers, the males of the species developing an arched back—hence the common name. Limia makes up a genus of live-bearing fi shes under the Poeciliidae family, which includes many popular aquarium species such as swordtails, mollies, guppies, and platys. Like most livebearers, males and females are quite easy to tell apart although they are often confused with other similar looking species such as Limia islai, a superficially species with almost the same body colour and black bar pattern to that of Limia nigrofasciata. Notably, L. islai males don't develop the humped backs in adulthood. The maximum length in males is approximately 5.5cm. Females are slightly smaller and duller in colour than males, but still possess distinct (albeit duller) vertical…