I have seen Lunare wrasse come up a bunch in this thread - but I honestly my terror fish is my Yellow tang - he steals silversided and urchin pieces right out of the mouth of my Odonus niger, he chases my lunare wrasse and thwacks him with his tail scalpals, he has torn chuncks out of the fins of my clark's clown, and he chases my humuhumu. I got him as a second hand tang from a reef buddy breaking down his tank. I named my tang Gimpy because he has always been missing half of his tail, and he has apparently suffered damage to his top fin which actually looks scarred. But despite the unhealed wounds suffered over his life, this tang is a murderous, meat eating, possessed devil fish - I though my trigger, being about twice the size and girth of the tang, would eat him - but instead he cowers in the corner when gimpy comes out and about. Honestly I have never even considered taking him out of the tank - my other fish are tough enough to deal with the tang abuse - and honestly my silverside eating cripple tang is just too funny to watch to even think about getting rid of -