Christmas tree worms (Spirobranchus giganteus) are abundant throughout the Sanctuary, and in many shades of color. The two "trees" are the gills of a worm - the body, which is embedded in the coral, may be nearly a meter in length. The worms shown here are inhabiting mustard hill coral (Porites astreoides). These animals usually withdraw into their tubes when approached but if you are still and patient, they will slowly extend. These animals have been documented spawning on the same evening as the mass broadcasting corals at the Flower Gardens. (photo: Frank and Joyce Burek)