This is so much more complicated than keeping monitor lizards, lol. I have so much to learn so I guess this being my first time around I should be easy on myself. The biggest polit seems to chase away the most dominant demasoni, most colorful specimen. You know I did my research, I have books on the evolution of cichlidae but I still feel lost, lol. Books have helped me very little as most books I have are old or only cover very basic things. I tried to match cichlids by aggression using the resources on this forum (fish profiles). I tried to keep them small as adults 4" or less since I only have a 55 gallon. I bought 15, five of each of the three species as I tried to keep the bioload down on newly cycled tank. So I can only hope to get a sex ratio that works out or maybe I'll have an all male tank or female (hope not).