Pearl Bubble Coral (Physogyra lichtensteini) Propagation Guide

How to propagate Physogyra lichtensteini (pearl bubble coral): cut the meandroid skeleton between its short valleys with bubbles deflated, and manage its day-and-night sweepers.

Overview

Physogyra lichtensteini, the pearl bubble coral, is a large-polyp stony coral in the family Plerogyridae found in the Indian and Pacific Oceans. It has smaller, pearl-shaped vesicles than Plerogyra, with a tear-drop finish, displayed during the day and replaced by open polyps at night. Colonies are generally massive and meandroid, with short, widely separated valleys, and it is common in lagoons and on reef slopes.

Reproductive Mode

Like its relatives in the Plerogyridae, the pearl bubble coral is propagated asexually in aquaria by dividing the skeleton between heads. Its massive, meandroid colony, built of short valleys interconnected by a light, blistery coenosteum, lets a keeper cut between the separate valleys to make new pieces. Fragging is possible when the cut follows the skeleton rather than the soft vesicles.

Fragging / Asexual Propagation

1. Work when the bubbles are deflated and the polyps and tentacles are pulled in.
2. Identify the short, widely separated valleys in the meandroid skeleton.
3. Cut carefully through the bare coenosteum and skeleton between valleys with a band saw.
4. Avoid cutting through the inflated pearl vesicles, which are delicate and tear easily.
5. Mount each piece in low flow and moderate light and let the tissue heal over the cut.

Dividing along the natural valleys of the meandroid skeleton keeps the vesicle tissue intact on each new piece.

Conditions for Propagation

Pearl bubble corals live in lagoons and on reef slopes to depths beyond 38 m and do best under moderate lighting and low flow that let the vesicles inflate. Stable temperature near 24-26 degrees Celsius, pH 8.1-8.4, and steady alkalinity, calcium, and magnesium support recovery of the cut frags.

Common Challenges

Pearl bubbles are hardy but aggressive: they can send out sweeper tentacles both day and night that sting neighboring corals, so frags must be placed with open space around them. The pearl vesicles are also delicate, so any cut should follow the skeleton and the coral must be handled gently while submerged.