I have vermatids that grow close to my SPS colonies and the coral encrusts over it's tube and basically encases it. It then turns into another branch off the colony. Haven't had any problems with them killing corals Steve. Nature takes it course and the SPS colony defends itself by basically overgrowing and suffocating the worm.vermetid snails will irritate and harm SPS in my experience. Ive lost a couple frags from these lil buggers. If you can destroy them I would, unfortunately I can not reach their tube to destroy them. Does anyone know of a predator to eat them...shrimp.