Palythoa grandis Propagation Guide

How to propagate Palythoa grandis, the large-polyped sun-polyp zoanthid, by dividing the colonial clusters, with strict palytoxin safety precautions.

Overview

Palythoa grandis (family Sphenopidae) is a large-polyped Palythoa often called a sun polyp, with single polyps growing to over two inches across - among the largest photosynthetic zoanthids kept by aquarists. Its polyps sit on a colonial coenenchyme mat. Reef Builders describes it as comparatively slow-growing and as one of the slimiest and most toxic of all zoanthids.

Reproductive Mode

This species is increased asexually. New polyps bud from the colonial mat, but growth is comparatively slow, so colonies build up gradually from one or two polyps over long periods. Propagation divides the colonial clusters once enough polyps have accumulated.

Fragging / Asexual Propagation

Because polyps are large and the colony slow to rebuild, frag conservatively. Following Reef Builders' zoanthid method, slice the mat between polyps with a razor blade and trace the line with coral cutters until a polyp or cluster frees, cutting close to the base. Mount the cluster on a plug and allow a long recovery.

Wear gloves, eye protection and a mask - this is one of the most toxic zoanthids.
Cut the colonial mat between large polyps with a fresh razor blade.
Trace the line with coral cutters until a polyp or cluster separates near the base.
Dry the plug and base, add a little glue, and seat the cluster gently.
Return it, blast off the copious mucus, and allow extended time to re-anchor 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
Large polyps accept meaty foods, which can support recovery

Palytoxin Safety

Palytoxin is one of the most poisonous non-protein substances known, and aquarists have been poisoned by contact and by inhaling aerosol when handling or removing Palythoa. Given how much mucus this species produces, eye and face protection is essential during any propagation work.

Common Challenges

Slow growth means a fragged colony takes a long time to rebuild, so over-fragging sets the parent back severely. The heavy mucus can smother fresh frags if not blasted off, and large polyps are easily damaged by deep cuts. Frag minimally, cut cleanly, and be patient through recovery.