Not a marine fish. Currently kept in a tank without live plants, is best kept this way. Can get very territorial, and are most suited to living with only their own kind. (Although we currently have a plec, and some phantom tetras with them) they are very beautiful. Will shed their blue every few months and become brown, but the blue comes back. They are currently around 12cm, this tends to be their maximum size. We have 3 to go.