Thats Easy.......Hands Down "UMBEE"............ They are bigger and more powerful then any other cichlid other then the Emporer. My Umbee whopped the **** out of my largest dovii so bad i had to get rid of it.......
believe it or not my late Firemouth was naaasty, he was beautiful but he bit off all the heads of the minnows i fed him, not even eating the whole thing, he just couldn't stand them, he even tried to fight me through the tank all the time, killed a pleco too
the meanest fish ive ever owned were my pair of orange pikes. killed everything i put in there. EVERYTHING. it was thier tank and they kept it that way. oh ya and my snakehead... ya my snakehead gets my vote. it killed every single fish in my tank and not like the 4 other fish i had with my pikes i mean the other 12 i had with him all bigger then he was to. snakehead gets it. bastard. i hate that fish.