I have a 3 striped damsel in my 44 gallon fish & invert. tank and he is the most aggressive fish I have, too. If I have anything in the water he will attack it, and he'll chase everyone around just for the heck of it. When he gets mad his first stripe turns a light grey color until he calms down again. I have a pair of percs, too, and they just seem to ignore him for the most part and do their own thing. I used to have a chocolate chip starfish and I had to sell him because he was eating all my turbo snails. He LOVED them. Other than that he was great. Good luck!