How large are the fish? What I am about to tell you is not always 100% the case, so don't hold it against me if they are not what you thought they were. Males in cichlids tend to be a little bigger, although in the tropical fish trade, many fishes genes have been altered a little through selective breeding whether intentionally or not. What I'm saying is that females and males may be closer to the same size. Good feeding and raising also can lead to females being the same size. Males also can have longer points at the ends of their fins while females have shorter fins. Not much shorter, but enough to tell if you look. Really, though, the best way to tell is when they spawn. If they are juvenile fishes you might as well wait because you just wont be able to tell until they get older.