The anemone is either a sebae of a pink haitian. Well, if the tang is allright, then let him stay. But, if he starts to get off colour, starts getting lazy or too big, get him out. They are brilliant fish, but they do need the room. I have mine in a 55, and thats crossing a couple of barriers, but he seems fine for now. Ya, dont jeapordize his health though. If he looks a little skrewy in a while, exchange him for something else.