what kind of fish? A Betta? Their so cute... One time we kept ours in a circular little tiny cuplike tank... made for bettas... then we bought him a spongebob tank.. when we put him in... all he did was swim in a circle.. his body was in a permanent c-shape from swimming in one direction in the cup-like tank... poor thing died a few days later... so we got a new one... he lived with spongebob for 2 years... when we moved I didnt want to take care of the spongebob tank anymore, being that we have a 29 gallon aquarium too.. so I poured him into the big aquarium with the others... he gets along fine with the communtiy fish... Although, all the wave in the big tank, make him swim more, so he has worn down all his pretty fins.. now he looks like an orpahn fish.. but he has friends and hes happy...
Sorry for the long Fish story! Sometimes I lose control!