Isophyllia rigida
Colonies are massive and corallites are usually single, sometimes forming short valleys of two or three dividing polyps, but never meandering or brain-like. It forms small domes with fleshy polyps and the calices or short series are irregular in outline. (It is similar in appearance to Acanthastrea of the Indopacific.)
It is usually grey or greenish, with centres and walls of different colours.
It is usually grey or greenish, with centres and walls of different colours.