I was wanting to get some cichlids for my 55g tank with a p. Sen in it. I was looking at the yellow lab cichlids and the Demasoni. I was wondering how many of each would live comfortably in my tank without much aggression. ive heard the Demasoni is aggressive towards others with the same coloring, and the lab is peacefull. The tank is over filtered with a penguin 350 and an emperor 400.