I wouldn't put anything else in there with him, he's going to need all that space to himself and probably more (going on if its a male), a female you could probably get away with in there, but I wouldn't add other cichlids, maybe a catfish you could get away with.
na mate if hes a male he will destroy it.. unless its a fish that will destroy him.. you cant really win with green terrors. i have a pair in a 6x2x2 and they kill anything i try to add.. its somthing i get over there great fish