Acropora carduus Propagation Guide

Propagating Acropora carduus, a bottlebrush SPS coral with spiky radial corallites, by fragmentation: cutting branch tips, mounting frags, and holding the stable chemistry, high light and flow that fragments require.

Overview

Acropora carduus is a bottlebrush stony coral in the family Acroporidae, named for the spiky radial corallites along its branches. Like other Acropora it grows as a colony of small polyps sharing tissue over a calcium carbonate skeleton, with symbiotic Symbiodinium algae providing energy through photosynthesis. The bottlebrush branches are fragged at the tips like other SPS.

Reproductive Mode

Acropora reproduce sexually through gamete release and asexually when fragments reattach and grow into new colonies. Aquarium and farm propagation use fragmentation because each frag carries the parent's genetics and resumes growth once secured.

Fragging / Asexual Propagation

Select a healthy, well-coloured branch tip from an established colony.
Cut or snap the branch with bone cutters or a saw, keeping the break clean.
Glue the frag to a plug or rock with cyanoacrylate or epoxy.
Set the frag in moderate light and flow until tissue grows over the cut.
Dip and quarantine new frags before introducing them to a display.

Under good reef conditions, finger-sized fragments can grow into much larger colonies within one to two years, so a single parent supplies many bottlebrush frags over time.

Conditions for Propagation

Fragments need stable conditions to heal. Acropora are especially prone to bleaching when stressed, which is caused by the loss of their zooxanthellae, so steady temperature, salinity, alkalinity, calcium and magnesium are critical. High light and high flow drive the dense skeletal growth this branching form needs.

Sexual Reproduction

In the wild, Acropora participate in annual mass-spawning, releasing gametes into the water for external fertilisation and larval development. This is rarely seen in home aquaria, so hobby propagation depends on fragmentation.