I kept a pair in a 20 gallon for a couple of months, but where starting to get to big so I sold them. They are quite skitish, and arent really the show when they eat like oscars are. Hard to keep fish in with them, and they can easily eat a fish that is twice as big around as they are. Takes lots of feeders to keep these things going and healthy. I wouldnt put them in with any fin nippers either, due to they are so skitish and can quickly jump out of the tank, or hurt themselves trying.