I currently have an orangeshoulder tang. Within the past week i noticed that it seems she rubbed herself against a rock. Usually i would think oh no a parasite. Well I have yet to see or or notice anything to the effect that wold cause her to rub. when i watch the tank she doesnt rub, at all. All the other fish are fine. It is a reef tank. Just in case should i try and treat the tank, and what would your recommendations be??