Found in all tropical waters, the Christmas tree worm is a favorite among divers for their colorful variations, unique shape, and ability to “disappear” when a diver gets too close! This segmented marine burrowing worm makes its home in live coral. In Hawaii, it is most often found on lobe coral and live a sedentary life, rarely moving from the hole they bore in the coral.
The part of the worm that we see as divers are the two Christmas tree shape fans composed of radioles (hair-like appendages) that protrude from the spine. These radioles are used in their respiratory functions and help collect food. If spooked, the worm can quickly retract its bristles into its burrow and fully close the opening to protect itself from predators.
Christmas tree worms are thought to live as long as 40 years! While they can be as large as an inch and a half in diameter in other parts of the world, they are often much smaller in Hawaii.
Next time you’re diving, look around for these cute, bristly creatures! You might even find a whole Christmas tree farm on a coral head!