There is no such thing as a guaranteed reef safe fish. I had sold a purple tang once and then chowed down on the persons coral. All four of my flame Angels have been reef safe,but they love to graze all day long. My tanks have always had plenty of algae for them to do that. If you really want one place it in a QT tank for a month and add a few corals to see how it does. One word of caution they will be king of the tank in a few years