Spirobranchus giganteus
Encounter Rate
Spotting Difficulty
Best Season
Year-round
Depth Range
1-30 meters
Christmas tree worms are among the most delightful and photogenic small creatures on Komodo's reefs, named for their twin spiralling crowns of feathery tentacles that bear a striking resemblance to miniature decorated Christmas trees. These polychaete worms live inside calcareous tubes that they build within living hard coral colonies, with only their colourful crowns protruding from the coral surface. The double-spiral crowns serve two functions: respiration and filter-feeding, with each radiole (branch) covered in fine cilia that trap plankton and organic particles while also absorbing oxygen from the water. Christmas tree worms come in an extraordinary range of colours including blue, orange, red, yellow, white, and multicoloured combinations, and several individuals often cluster together on a single coral head, creating a garden of tiny, jewel-like trees. In Komodo, they are ubiquitous on healthy coral reefs and are one of the most accessible and rewarding macro photography subjects available. Their hair-trigger retraction speed — disappearing into their tube in a fraction of a second when disturbed — provides an entertaining challenge for photographers.
Average Size
1.5-3cm crown diameter
Size Range
0.5-4cm crown diameter
Maximum Size
4cm crown diameter, tube up to 20cm long within coral
Filter feeder that captures phytoplankton, zooplankton, and organic particles from the water using cilia-covered radioles on its spiral crowns.
Christmas tree worms are among the most delightful and photogenic small creatures on Komodo's reefs, named for their twin spiralling crowns of feathery tentacles that bear a striking resemblance to miniature decorated Christmas trees. These polychaete worms live inside calcareous tubes that they build within living hard coral colonies, with only their colourful crowns protruding from the coral surface. The double-spiral crowns serve two functions: respiration and filter-feeding, with each radiole (branch) covered in fine cilia that trap plankton and organic particles while also absorbing oxygen from the water. Christmas tree worms come in an extraordinary range of colours including blue, orange, red, yellow, white, and multicoloured combinations, and several individuals often cluster together on a single coral head, creating a garden of tiny, jewel-like trees. In Komodo, they are ubiquitous on healthy coral reefs and are one of the most accessible and rewarding macro photography subjects available. Their hair-trigger retraction speed — disappearing into their tube in a fraction of a second when disturbed — provides an entertaining challenge for photographers.
This species plays an important role in the marine ecosystem of Komodo National Park. Responsible diving practices help protect these animals and their habitat for future generations.
No encounters shared yet
Be the first to share your sighting of this species!
Their crowns are vulnerable to predation by fish and other animals. The lightning-fast retraction is a defensive reflex triggered by changes in light (shadows) and water movement (vibrations). They re-emerge after 1-2 minutes once they sense safety.
