I agree with cichasoman, (especially about breding) but to avoid aggression, keeping species of a different genus together seems to work for me.
I have kept Paretroplus maculatus with Paratilapia, and even Ptychochromis species together, if they are relatively similar in size, and the tank is large enough.
The tank below is 6ft 130 gal, there are 4 Paratilapia, 4 Paretroplus maculatus (medium age), and some small/young Central Americans
click to run video.