The Hard Tube Coco Worm, Protula bispiralis, also known as the Hard Tube Feather Duster, Protula Tubeworm, or Hard Tubeworm, features a varied colored feathery crown protruding from a calcareous tube. The tube will attach to sandy or rocky substrate and the radiole will protrude filtering the water column for food. This species is incredibly intolerant of poor water quality and should not be kept with predatory fish, urchins, or serpent starfish. This tubeworm is an excellent addition to any reef tank as it is relatively easy to care for and adds a splash of color and diversity to most tanks.