If it's resulting in physical damage, it's time to separate them IMHO. I just had to separate my pair, after many years together. Not sure why, but the female just turned on the male and tried to kill him. I separated them until his wounds healed, them put them back together, and she did it again. Maybe he is turning into a she? IDK. It's highly likely that one of your fish will die if not separated. I also agree with shaggss. An anemone will simply fan the flames.