Porites – Christmas Tree Worm Rock (Porites sp. & Spirobranchus sp.)

Christmas Tree Worm Rock is a living entity formed by two different reef animals. The surface of the rock is covered by SPS stony coral of the genus Porites, within whose calcareous skeleton live several small Spirobranchus tube worms, also known as Christmas Tree Worms.

Porites forms living coral tissue on the surface of the rock and gradually grows around the worms' calcareous tubes. The most visible part of the worms is a two-part, spiral fan, which can be, for example, white, yellow, orange, red, blue, or multi-colored. Each rock is unique, and the number and colors of the worms vary individually.

Spirobranchus worms use their fans for breathing and filtering fine particulate food from the water. When they detect a disturbance, they retract their fans lightning-fast into their calcareous tubes and re-open them once the situation calms down.

Porites and Spirobranchus also occur together in nature. The worm builds its own calcareous tube, which, as the coral grows, merges to become part of the Porites coral's calcareous skeleton. In an aquarium, the needs of both animals must be met separately.

Features

• Living Porites SPS coral and several Spirobranchus tube worms on the same rock
• The worms' small spiral fans can be various colors
• Porites grows around the worms' calcareous tubes
• Fans retract instantly for protection when sensing a disturbance
• Combines the growth of stony coral with the continuous movement of filtering tube worms

Porites Coral Care

Porites is a small-polyped SPS stony coral that thrives in a stable and mature reef aquarium. It requires sufficient light for photosynthesis and good water flow.

• Lighting: Strong. Approximately 150–250+ PAR is a good starting point. Acclimatize the coral to stronger lighting gradually.
• Flow: Moderate–strong and varied. Water should move well around the coral, but avoid directing a continuous strong jet of water at the worms' fans.
• Water parameters: Stable KH, calcium, and magnesium levels suitable for SPS coral are important for the growth of the calcareous skeleton. Avoid rapid changes in water chemistry.

Spirobranchus Tube Worm Care

Tube worms do not derive energy from light but filter their food from the water. Regular intake of fine particulate food is important for their long-term care.

Feeding: Phytoplankton, rotifers, and other very fine plankton and coral foods. A diverse diet of small-sized food is a better option than relying on a single food type.

Food should be dispensed slightly upstream of the rock so that the current carries it to the fans. Avoid spraying food directly at the worms, as they can easily retract into their tubes due to water movement or other disturbances.

Care Instructions

• Aquarium: Mature and biologically stable reef aquarium
• Temperature: 24–26 °C
• Salinity: 34–35 ppt
• Lighting: Strong, approximately 150–250+ PAR
• Flow: Moderate–strong, varied, and indirect
• Feeding: Regularly phytoplankton and other fine plankton food
• Difficulty level: Demanding

Note

Christmas Tree Worm Rock is not recommended for treatment with standard coral pest dips, as treatment intended for coral can harm the tube worms living within it.

Tube worms are also extremely sensitive to copper. Copper-based medications must not be used in an aquarium where they are kept.

Additional Information

• Coral: Porites sp.
• Tube worms: Spirobranchus sp.
• Family, coral: Poritidae
• Family, tube worms: Serpulidae
• Trade name: Christmas Tree Worm Rock / Bisma Worm Rock
• Origin: Indonesia
• Difficulty level: Demanding