Clove Polyp

The clove polyp is a soft coral made of polyps rising one by one from thin, ribbon-like bases (stolons) that spread over the surface of the rock. Each polyp carries eight broad, feathery tentacles opening on a short tube; when open, the tentacles give a star- or flower-like appearance. Its colors are brown, green, cream or purple, and the area around the mouth is often lighter or fluorescent. The polyps quickly retract into the tube when touched or bumped by a fish.

In the trade the name "clove polyp" is used for Clavularia species as well as for Knopia, whose tentacles have fused side projections; Clavularia's tentacles are distinctly feathery. It is a hardy, easily propagated coral that is not covered by CITES.

On shallow reefs of the Indo-Pacific it forms wide but sparse colonies on dead coral, rock and rubble, generally in places that receive light and flow.

• Light: Moderate light (roughly 80–200 PAR). Under very strong, direct light the polyps may close; under low light the color fades.
• Flow: Moderate, indirect flow. Direct strong flow keeps the polyps from opening; in very weak flow detritus and filamentous algae build up around the base.
• Placement: The middle part of the rockwork or a separate stone. It spreads slowly via its stolons.
• Water parameters: Salinity 1.024–1.026; KH 7–11 dKH, calcium 400–450 mg/L, magnesium 1250–1350 mg/L. Phosphate should be kept low but not at zero.

It gets most of its nutrition from photosynthesis. Its polyps can take very fine food particles; phytoplankton or powdered food can be given once a week, but this is not essential for a healthy colony.

It does not attack neighboring corals; it has no stinging tentacles and no strong chemical defense. Its stolons can advance over the rock and creep in at the base of other corals, so leave 10 cm of space between it and its neighbors. It is itself weak against stinging LPS and anemones.

It is compatible with fish and the cleanup crew. Some dwarf angelfish and butterflyfish may pick at the polyps; a colony that is constantly picked at stops opening.

A polyp-bearing section of the stolon is cut and tied to a small stone with a rubber band or attached with glue. Another way is to place a bare stone next to the colony, wait for the stolons to spread onto it, and then cut the connection between the two stones.

• Polyps not opening: Direct strong flow, sudden changes in light and fish picking at them are the most common causes.
• Algae at the base: If flow is weak, filamentous algae grow between the stolons and smother the polyps; increase flow and reduce nutrients.
• Polyp loss: If the colony is thinning out, check whether the light is sufficient and the water parameters are stable.