Platygyra daedalea (Maze Brain Coral) Propagation Guide

Propagation of the maze brain coral Platygyra daedalea (Merulinidae): cutting through the meandering colony skeleton to make frags, plus its broadcast spawning on the reef.

Overview

Platygyra daedalea is a maze brain coral in the family Merulinidae, recognised by meandering valleys with low, often perforated walls running across a single skeleton. It typically forms massive dome or boulder-shaped colonies that can reach a metre or more across, and is listed as Least Concern by the IUCN. As a continuous colony, it is propagated by dividing the skeleton rather than by separating heads.

Reproductive Mode

The colony enlarges asexually as polyps bud along the meandering valleys, extending tissue over fresh skeleton. Platygyra is also a hermaphrodite that reproduces sexually by broadcast spawning; studies note it can even self-fertilise as a reproductive assurance during smaller spawning events. Hobby propagation uses the asexual route, dividing the existing colony.

Fragging / Asexual Propagation

Select a well-coloured colony with extended polyps and identify a low valley wall as a cut line.
Saw cleanly through the skeleton with a band saw so each frag keeps continuous valleys and polyps.
Rinse off skeletal debris and glue each frag skeleton-side down to a plug or rock.
Recover in moderate flow under reduced light until the cut edge tissues over.

Conditions for Propagation

Stable alkalinity and calcium for skeletal regrowth at the cut.
Clean, moderate flow over the fresh edge.
Subdued lighting immediately after fragging.
Low nutrients to keep exposed skeleton free of nuisance algae.

Sexual Reproduction

On reefs, Platygyra participates in synchronised mass spawning, releasing gametes into the water column over one or two nights per year for external fertilisation. The resulting larvae settle to found genetically new colonies. This is not a routine aquarium propagation pathway.

Common Challenges

Maze brains are among the hardier brain corals, but exposed skeleton after a cut is vulnerable to algae and tissue recession if flow or water quality lapse. Crushing rather than slicing the skeleton damages the bordering polyps, so use a saw rather than blunt cutters.