How do I keep a puffer?

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A reader asks for advice on keeping Dwarf puffers in a 60 litre tank.

Please could you give me some information on keeping Dwarf puffers? Would they be okay in a 60 l tank, and how many should I keep in a group? Advice on feeding would also be welcome.

SIMON HENDERSON, VIA EMAIL

Neale says: Dwarf puffers, Carinotetraodon travancoricus, are not especially difficult to keep, but the usual pufferfish conditions apply. They are territorial, sensitive to ‘old’ water, and aren’t going to eat the usual flake and pellets. On the other hand, again much like other puffers, they’re largely indifferent to water chemistry provided extremes are avoided, and compared to many other fish, exhibit a degree of curiosity about the outside world that makes them unusually engaging pet fish.

I’d suggest a tank not less than 35 l in size as the bare minimum. While some people do keep them in smaller tanks, a larger one offers better insurance against problems, especially changes in water quality. They appreciate regular water changes, and the bigger the tank, the easier it is to keep nitrate levels low. Aiming to give each specimen 10 l is a good rule of thumb with these fish, so, your 60 l tank should house something like half a dozen specimens or so. Males tend to be more feisty than females, and the more complex their environment in terms of plants and other ‘line of sight’ breaks, the better the fish will tolerate one another. Clumps of Java moss work really well, but I’d also add some taller plant species, such as hardy Cryptocoryne species to create some cover further up the water column. Floating plants are appreciated, and encourage fish to swim at the top of the tank.

So far as feeding goes, not much is known about what these fish eat in the wild, though insects and crustaceans have been reported to make up more than half their diet. Under aquarium conditions, though, they feed on all the usual things other puffers like to take, such as snails and bloodworms, but you will need to make sure such foods are small enough to be taken by these tiny fish. You will need to offer enough crunchy foods to keep the growth of their beaks in check, but Dwarf puffers aren’t as prone to overgrown beaks as some of the other pufferfish species kept by aquarists (I’m looking at you, Colomesus asellus).