Acropora millepora: Propagation Guide

Propagating the branching SPS Acropora millepora by snapping or cutting branch tips and gluing them to plugs, with mass-spawning biology and RTN warnings.

Overview

Acropora millepora is a small colonial coral of the family Acroporidae that grows in clumps of short, cylindrical branches; its radial corallites are all the same size with projecting lower rims, giving a scale-like appearance. It grows in shallow water between two and twelve metres deep on reef flats, upper reef slopes, and in lagoons, from the Red Sea and East Africa to Japan, Indonesia, and Australia, and is zooxanthellate.

Reproductive Mode

Acropora corals reproduce sexually during mass spawning events and asexually through fragmentation, which occurs naturally when branches break. In the aquarium fragmentation is the standard method: finger-sized fragments can grow into medicine-ball-sized colonies in one to two years under good conditions.

Fragging / Asexual Propagation

A branch tip is removed with bone cutters or a coral saw, the plug is soaked, both the plug and the cut base are dried, and a bead of cyanoacrylate glue roughly the size of the frag base is applied before pressing the frag in place for about thirty seconds. A few hours later the frag should be back in good flow and light, where the polyps extend and the coral begins to encrust the plug.

Conditions for Propagation

Acropora demands bright light, stable temperature, regular calcium and alkalinity supplementation, and clean, turbulent water. New frags can be started in slightly lower light and flow, then moved up as the tissue seals and the polyps extend normally.

Common Challenges

Listed by the IUCN as Near Threatened in the wild, Acropora millepora is susceptible to bleaching and coral diseases and to RTN/STN, which can be triggered by unstable water quality, stress, or shipping. Keeping an insurance frag of any colony showing necrosis is standard practice.