"Spirobranchus giganteus", commonly known as the Christmas Tree worm, is a tube-building polychaete worm belonging to the central family "Serpulidae". Both its common and Latin names refer to the two chromatically hued spiral structures, the most common feature seen by divers. The multicolored spirals are highly derived structures for feeding and respiration.

Christmas Tree worms are found living in coral reefs around the world.

Female worms release eggs into the water where male worms have released sperm. The fertilized eggs develop into larvae that then settle on coral heads and begin burrowing in to form their homes

"Spirobranchus giganteus" is similar to most tube-building polychaetes. It has a tubular, segmented body of an approximate length of 3.8 cm (1.5 in) covered with chaetae, small appendages that aid the worm's mobility. Because it does not move outside its tube, this worm does not have any specialized appendages for movement or swimming.

The worms' most distinct features are two "crowns" shaped like Christmas trees. These are highly modified prostomial palps, which are specialized mouth appendages.

Each spiral is composed of feather-like tentacles called radioles, which are heavily ciliated and cause any prey trapped in them to be transported to the worm's mouth.

The species is widespread and relatively common, there is no conservation efforts focused on the Christmas Tree worm.

More Info: en.m.wikipedia.org