my female is about 3.5" and she is with my thread fin acara, salvini, 2 bristlenose plecs and a convict she is the 2nd biggest in the tank with the thread fin being 4" and there is no aggression what so ever but i will wait till they get bigger but if they have grown together then i dont see why there will be any aggression basically any fish that can stick up for itself and grows larger than 5" is okay such things as: green terrors, convicts, firemouth, blue acara those type of cichlids are fine