Choosing Tank Mates: Building a Peaceful Community
Temperament, water parameters and adult size decide whether a community works.
A community tank fails for predictable reasons: someone grew too big, someone needed different water, or two species that should never share a tank were sold together anyway.
Check three things before you buy
- Adult size. That 4 cm fish may reach 30 cm. Look it up, not at the tank label.
- Water parameters. Temperature and hardness have to overlap. Goldfish are cold water; most tropicals are not.
- Temperament. Fin-nippers, territorial cichlids and anything that fits another fish in its mouth need careful pairing.
Stock in shoals
Tetras, rasboras, danios and corydoras are shoaling species. Six is a minimum and more is better — kept in twos and threes they become stressed, pale and nippy. Half the "aggressive tetra" reports come from under-stocked shoals.
Use the whole tank
Pick species from different levels: surface, mid-water and bottom. It looks better and reduces competition.
Bettas
Male bettas cannot be housed together, and they will attack anything long-finned and colourful. Peaceful bottom dwellers are the safest companions, in a tank of 20 litres or more.
Add slowly
A few fish at a time with two weeks between additions, so the filter can catch up.
