as far as i new a Harlequin Tusk is a member of the wrasse family? but there are a few smaller fish i will add that are not on the lise royal gramma , sixline wrasse and such im not to concerned about the normal "reef safe" as long as they leave the ricrock alone fish as most of these guys eat hermits and shrimp including the larger tangs which have also eating a chromis or 2 when it got to close during feeding time