Definitly a damsel, almost certainly yellow or gold. (Amblyglyphidodon aureus) this one appears to be a mature adult lacking in the fresh from the pet store juvenile coloration. Great feeder fish or cycle fish. Mean Mean Mean little sucker can back off a fish 5X it's size successfully but is still primarily a scavenger/Vegetarian. definitly not community tank fish but great for a reef tank as the only fish.