Best Fish for a 40-Gallon Tank

Edited by Ivan F.

A 40-gallon opens up larger schools and bigger species, and it is far more forgiving of small mistakes.

How we pick: Species whose minimum tank size is within 10% of 40 US gallons or smaller. Group size still counts: always check how many fish a species needs.

Fitting the same tank size does not mean these species can live together. Check each species' tank mates before you buy.