These beautiful colonies of miniature Feather Dusters make a great addition to any reef tank. The Duster Cluster is a group of small tubeworms. A worm lives within the tan tube of each tiny Feather Duster, and this worm carries a colorful "crown" of feathers. These feathers are pushed up throw the opening of the tube and act as a catching device for food, which is collected by the worm's mouth at the base of the feathers. The worm uses the tube as protection and will quickly pull in the feathered crown when it detects a predator. They will multiply rapidly in optimum water quality. They should be placed together in an area of low water flow.Feather Dusters are not often thought of as worms because what most people see is just the pretty feathery "crown" the worm uses to capture food. But there truly is a worm living inside the Feather Duster's tan tube. They create this tube by combining sand and a special secretion in order to protect their delicate body. The feathery crown, also called a "radiole", is an extention of the mouth of the worm and serves as both its gills and a way to capture food. Feather Dusters are very light sensitive and will quickly retract when approached or disturbed. Feather Dusters are known to "throw" their crowns which usually regrow within a few weeks.