Dottybacks are considered to be reef safe for the most part, but as frankc said there's always the chance of a rogue one. With them usually it's fin nipping that you have to be more worried about than taking a chunk out of a coral. Dip the coral in an iodine solution and put it in a different spot and keep good flow across it, and observe the tank inhabitants to see if anything shows particular interest in it after being moved.