Christmas Tree Worm

The Christmas tree worm (Spirobranchus giganteus), also known as the “Christmas tree,” is a species of polychaete worms from the Serpulidae family. Widely distributed in tropical seas of the World Ocean. They lead a sessile lifestyle in close association with stony corals, building calcareous tubes in depressions on the surface of their colonies.

The branches of the “Christmas tree” in the marine worm are organs of respiration and digestion. With their help, it filters water, obtaining nutrients and oxygen. Its feathery tentacles help it move through the water. Tube-dwelling polychaete worms can barely swim and lead a sessile lifestyle.

The polychaete worm lives in a calcareous tube, which it builds itself, extracting calcium ions from the water and binding them with saliva. Each time, this tube is replenished with new rings and increases in size.

Most often, Christmas tree worms inhabit large coral species, such as stony corals, for example, porites, and brain corals. When the Christmas tree worm retreats into its tube, it can seal it by closing with a lid-like structure called an operculum, which is additionally protected by sharp spines. Very sensitive to danger, at the slightest touch or even a falling shadow, they quickly retreat into their burrows.

Like a Christmas tree, marine worms are colored in rich colors, their shades can be completely different colors: yellow, red, blue, black, pink, white, etc. The marine worm can be found at shallow depths among corals.

Spirobranchus giganteus live differently, everything depends on the species: smaller worms – several months, while larger species – up to 4-8 years.