i have a 4" pike cichlid with two 5" oscars, a 5" peacock bass, 3 convicts, a firemouth, and a nicoroquensis. the pike minds his own business for the most part. my tank is extremely aggressive but he leaves the other fish alone unless he is defending himself (which he has proven more then capable of doing.) as long as he is relativley the same size as your other fish he will be fine. i bought my best friend a 4" pike and he is kept with a texas, and two red devils. one is 8" and one is 10". the pike is fine. these fish are really tough, i would be more concerned about the other fish in the tank. but then again i guess itd depend upon the personality of the fish.