Characters: Colonies are massive, usually hemispherical and often over 0.5 metres across. Corallites are up to 25 millimetres diameter and cerioid, becoming plocoid on the colony sides. Septa are mostly uniform, with large teeth. Colonies have thick fleshy tissue over the skeleton. Colour: Uniform blue-grey or mixtures of grey, brown, cream and green, usually with mouth, oral disc and walls of contrasting colours. Similar species: Acanthastrea hillae, which has smaller corallites with a tendency to form valleys. Resembles Symphyllia erythraea underwater. Habitat: Shallow, partly protected reef environments. Abundance: Uncommon but conspicuous.