it is amazing how these fish can take on there own personality , for good and most times bad. i have seen some dominos get really nasty once they get bigger. fish in a sense are like people give them something to fight over and they will ,, with fish its a rock , corner, powerhead , tubing,overflow box, open area , filter intake tube , or the whole tank which the fish thinks he owns, ,, :happyfish , and they fight to the death for it..