Bristle worm colony. Colony of polychaete tube worms or bristle worms on a coral reef. These are Filogranella elatensis tube worms, part of the sub-order Sabellidae (feather duster worms). These marine annelid worms secrete a rigid, calcareous (calcium carbonate-containing) tube from their bodies, which they withdraw into when threatened. The tentacles seen here are used to filter food from the water. Filmed in Raja Ampat, West Papua, Indonesia.