Community tanks are the most abundant aquaria out there, but they’re also prone to some easily avoidable compatibility problems.
WORDS: NATHAN HILL
THE COMMUNITY TANK is the staple of the aquarium hobby. But almost every community aquarium out there is an experiment in progress, with the livestock the victims when our ‘try it and see’ attitude doesn’t quite pan out. I see many easily avoided mistakes being made with mixed-fish layouts.
What is a community tank?
At its most basic, a community tank contains any mixture of fish that wouldn’t exist together in the wild. When the term was first coined many decades ago, such communities were planned with a limited selection of fish, chosen for their ability to tolerate each other. As such, there was a loose ‘safe list’ of compatible fishes that could cohabit agreeably together. Alas, as fish availability has increased over the years, so have the variables, making ‘community’ much harder to define.
Feeding
Some fish actively seek out food, others wait for it to come to them. Put the two together, and one is going to miss out. This is a common pitfall of communities that house lots of different species together.
If a fish is slow and secretive in a shop’s tank, it’ll likely be the same at home. If you’re investing in such a fish (maybe a banjo catfish, or even a shy Corydoras species) then you need to consider long-term feeding. That could be as simple as adding some dedicated catfish food after dark, or you may need to target feed them with a pipette.
With Corydoras in a bustling tank, consider piping some defrosted bloodworm directly into the upper layer of sand in their tank. They’ll find it at their leisure while their tankmates will be oblivious.
What you don’t want to do it just throw in loads of extra food in the hope that some will make it to the shyest fish. Such behaviour will soon lead to a polluted tank.
Territory
Some fish understand (and make) territorial boundaries while others don’t. Cichlids in particular are notorious for claiming a part of the tank when spawning, while most catfish are notorious for blundering across the invisible borders the cichlids have set.
If choosing territorial fishes, you do so at the expense of everything else in the tank. With smaller territorial fishes like kribensis, this might be acceptable to the other residents, but if you want to have an especially harmonious mix
