Rather than forming colonies like most other corals, this mushroom coral is solitary and free-living; that is, it is not attached to the substrate (except for juveniles). The coral is flat with a large central mouth. The soft tissue surrounding the mouth is striped. The long dark purple or green tentacles with pale tips are extended day and night, and are similar to those of giant anemones. Very young Heliofungia (called acanthocauli) bear little resemblance to the adult form; they are shaped like flattened discs and are attached to the substrate via a stalk. Their resemblance to mushrooms gives these corals their common name. Heliofungia actiniformis used to be considered part of the Fungia genus, however, whilst the skeletons and habitat are very similar, they differ in their polyp structure (2).