LUNGFISH: Can I keep these fish?

While it’s possible to keep lungfish at home, you need to be aware that they are a big responsibility, in every way, and not without their risks. It’s most likely that you’ll come across the African species if shopping for one, so those are the ones we’ll focus on here.

Most obviously, their size needs to be considered. These are big fish, which may have an amphibian charm about them when young, but will soon grow large — even the smaller species, in aquarium conditions, can easily surpass 75cm, while in the wild at least one species is known to reach some 2m fully grown. On the plus side, they don’t require much swimming space, and a tank of 300x100x100cm should accommodate one of the smaller species well into adulthood.

Because lungfish are obligatory air breathers, the tank will require an ample region of air at the top. It’s important that this air is kept warm and humid, as a gulp of icy cold, English winter air could be detrimental to them, but it’s perhaps more important to ensure that the lid of the tank is secure. This is as much to stop naïve guests placing their fingers into the tank with the fish, which are more than capable of seriously damaging a hand, as it is to stop the fish getting out. For the same reason, you should never entertain the idea of hand feeding any lungfish. Decoration is easy, because lungfish simply don’t care. Pay some attention to substrate and make it as soft as possible — a fine sand will work well, though wild fish dwell on mud. Maybe provide some cover in the form of large branches or bogwood, but don’t overthink it. After all, you’ll want to get in there occasionally to remove uneaten food, and you want to keep such ‘hands on’ moments as brief as possible.

Feeding should be a mixture of large meaty foods, and occasional doses of greenery. One trick is to gut-load whole fish with greenery like spinach before offering it, so that the fish gets an omnivorous diet. Feeding frequency needn’t be too high, as wild lungfish often go for weeks between meals, so three feeds a week will be ample. Just note that if you’re feeding infrequently you’ll need to keep an eye on water quality issues — intermittent, large, protein-rich feeds like whole fish can cause sudden spikes in pollution. An oversized canister filter will help keep this in check, but may not completely control the problem.

For temperature, keep the water in the high-20s (24-30°C), and for chemistry aim for a pH somewhere around neutral and a hardness of 2-16°H. African lungfish are pretty tolerant of everything but the extremes.