Ridge Coral (Merulina ampliata): Propagation Guide

Propagating Merulina ampliata, a plating ridge coral with radiating valleys, by sawing plate sections, plus notes on its multiform colony growth.

Overview

Merulina ampliata is the type species of the genus Merulina in the family Merulinidae, named by Ehrenberg in 1834. Its colonies can be laminar, foliose, columnar, or arborescent, and a single colony can adopt all of these forms; on flat plates the valleys radiate from the centre and become contorted on branching structures, producing the lettuce-like ridge pattern. The genus ranges across the Indo-Pacific from the Red Sea to Japan and the southern central Pacific.

Reproductive Mode

Merulina is a colonial reef-building stony coral. Like other Merulinidae it reproduces sexually by releasing gametes into the water, but in aquaria the colony is multiplied asexually by cutting the plate. Its tendency to switch growth forms means a flat frag may later throw up ridges and branches as it matures.

Fragging / Asexual Propagation

Plating Merulina is fragged by cutting sections of the plate, ideally along the radiating valleys so each piece keeps several intact ridges with live tissue. A band saw gives a clean cut through the skeleton; frags are dipped, dried, glued to plugs, and returned to gentle flow and light to encrust and resume plating.

Conditions for Propagation

Healing frags do best under medium light and moderate flow that keeps detritus off the plate without scouring the tissue. Stable alkalinity and calcium feed the skeletal growth that lets the frag re-cover its cut edge and extend new ridges.

Common Challenges

Detritus settling in the valleys of a flat frag during healing can cause tissue recession if flow is too low. The species can also overgrow or shade slower neighbors as it plates outward, so frags need clearance from other corals.