I had a fairy wrasse before n it was suppose to be a peaceful fish. It was fine for a week then my angel n clownfish started to act different. I was watching them n seen the wrasse run into my angel hard. I seen that n got him out n took him back ASAP. As soon as I did that my fishes went right back to their normal crazy selves. So if I were u I would take him out cuse he probably won't change IMO
. It's probably just that one fish, maybe try exchanging him for a different but same fish.