Christmas Tree Worm

Fascinating facts about the Christmas Tree Worm

• The tube they build inside the coral is reinforced with calcium carbonate secreted from a collar around their neck — essentially, they manufacture their own home.
• They reproduce by releasing eggs and sperm simultaneously into the water column, where fertilisation happens by chance. Larvae drift for days before landing on a coral and beginning to bore.
• Their sensitivity is so high they will retract if a diver's shadow passes over them, which makes underwater photography a slow and patient exercise.

At a glance

About the Christmas Tree Worm

Christmas Tree Worms are marine polychaete worms that bore permanent tubes into living coral. The two vivid spiral crowns sticking out of the coral are not flowers — they are breathing gills that double as feeding fans, filtering tiny organisms from the water. They come in almost every colour imaginable.

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