Ahhh, this is the Melanochromis auatus.... just hang on, because he is just getting used to the tank. Pretty soon the boys will be calling him Rambo, as he is quite the chaser, and a bit aggressive. But hopefully the size of your tank will mellow him out somewhat. I don't recommend this species for community tanks because of their aggression. So keep an eye one him. If he gets too rough, he may have to go back as trade in.