My experience with these is that they know who to avoid, and generally do their own thing in a tank without interfering. They do like to hide, and should have some good caves to hide in. when they are out and about they are high speed and fun to watch. they hunt in the dark more than the daylight, and they get big enough that most cichlids will leave them alone unless they are breeding. I have kept them with Firemouths, JD's, Oscars, and GT's and never had any trouble. They have more difficulty in a tank with fin nippers than they do with big cichlids