Christmas Tree Worm

Geographical Origin and Habitat: Globally distributed across tropical coral reefs (circumtropical). Lives in an obligate symbiotic relationship with massive stony corals, especially of the genus Porites.

Taxonomy: Member of the Serpulidae family. Excavates a calcareous tube inside the coral host. Possesses two brightly colored, spiral-shaped crowns of radioles used for breathing and filtering food. Length is about 4 cm.

Social Behavior: Sessile and extremely shy. Retracts its crowns instantly into its protective tube and closes it with an operculum at the slightest shadow or vibration.

Coloration and Sexual Dimorphism: Spiraled crowns display a vast range of vibrant colors: bright blue, red, yellow, orange, white, and pink. Separate sexes with no visible dimorphism.

Tank Setup: Requires a stable marine aquarium. Since it resides within living Porites colonies, strong lighting and flow.

Diet and Feeding: Suspension filter feeder. Consumes phytoplankton, fine zooplankton, and suspended organic detritus. Requires daily target feeding of micronized foods.

Water Quality: Specific gravity 1.023-1.025, pH 8.1-8.4, temperature 22°C-26°C. Maintain calcium levels (400-440 ppm) to allow the worm to calcify its protective tube.

Compatibility and Tankmates: Completely reef-safe. Avoid keeping with fish that bite at corals or feather dusters, such as butterflyfish or some angelfish, which will scare the worm into permanent retraction.

Aquarium Breeding: Broadcast spawner, releasing eggs and sperm. Reproduction in captive aquariums is not viable due to filtration and predation on the pelagic larval stage.

Risks and Diseases: The death of the host coral generally leads to the slow decline and death of the worm. Copper-based medications are highly lethal.