Palythoa caribaeorum Propagation Guide

How to propagate Palythoa caribaeorum, the Caribbean sea-mat that forms large encrusting reef-flat colonies, by dividing the colonial mat, with strict palytoxin safety.

Overview

Palythoa caribaeorum is a Caribbean Palythoa (family Sphenopidae) commonly called sea mat. Its polyps are partially embedded in an encrusting mat of tissue (coenenchyme) over the substrate, and the species forms large encrusting colonies on shallow reef flats where it competes aggressively for space. The polyps are golden to tan, lie low, and open only partway. Like other Palythoa, it is photosynthetic and contains palytoxin.

Reproductive Mode

In aquaria this species is increased asexually. New polyps bud from the colonial coenenchyme mat, and the colony spreads outward across rock, encrusting and competing for space as it does on natural reef flats. Propagation harvests sections of this colonial mat rather than relying on sexual reproduction.

Fragging / Asexual Propagation

Because the polyps share a continuous mat, propagation means dividing the colonial tissue. Following Reef Builders' zoanthid method, slice through the mat between polyp clusters with a razor blade, then trace the cut with coral cutters until a section frees, cutting close to the base. Mount the divided cluster on a plug and let it re-encrust.

1. Wear gloves and eye protection - Palythoa palytoxin levels are notably high.
2. Cut through the colonial mat between polyp clusters with a fresh razor blade.
3. Trace the line with coral cutters until a cluster separates near the base.
4. Dry the plug and cluster base, add a little glue, and seat it gently.
5. Return it, baster off the heavy mucus, and let the mat re-encrust and bud.

Conditions for Propagation

• Lighting: 75-200 PAR (medium)
• Flow: medium
• Temperature: 24-26 degC
• pH: 8.1-8.4; salinity 1.024-1.026
• Nitrate below 15 ppm, phosphate below 0.1 ppm

Palytoxin Safety

Palytoxin is one of the most poisonous non-protein substances known, and home aquarists in the USA, Germany and the UK have been poisoned by skin contact or by inhaling aerosol when removing or boiling Palythoa. Treat this species with the highest caution during any propagation work.

Common Challenges

The colony secretes heavy mucus when cut, which can smother a fresh frag if not blasted off. Excess glue, deep cuts into the coenenchyme, and unstable parameters also stall recovery. Because the species encrusts aggressively, place frags where outward spread will not smother slower neighbours.