well i purchased a sailfin tang(zebrasoma desjardini) 7 days ago, and have found an easy way to tell if this one is going to be aggressive towards any fish i might put in with it. it has been peaceful with the fish that were already in the tank with it. its about 7 inches long, and loves for you to pet it. i bought it from iland aquatics. i usually use my magnet cleaner to hold its food at the side of the tank, but today when i decided to use it to scrap the tank, the sialfin became a much darker color and kept swatting the magnet on the inside with its tail. within 3 secounds of stopping the tang had returned to its original color, and was waiting at the top where i usually feed him. i have never had a mean tang before and they have always gotten along fine with my other tank inhabitants. so i guess my question is, if he hapens to swatt me with his tail while im feeding him, how bad is it gonna hurt? has anyo9ne ever had a tang swatt them before?