Millepora dichotoma

Millepora dichotoma, the net fire coral, is a species of hydrozoan, consisting of a colony of polyps with a calcareous skeleton. Part of the metabolism of the fire coral relies on zooxanthellae included in their anatomy. They are found from the Red Sea to Samoa and South Africa. They form fan-shaped colonies up to 60 cm across, but clumps may be several metres across. Coloured mustard to olive-yellow, the fans form in a single plane. Feeding polyps snare plankton from the passing current along exposed portions of upper reef slopes up to 15 m depth, growing transverse to the prevailing current to ensure maximum exposure to passing foodstuff. The stinging nematocysts contain a toxin which causes painful burn-like wounds on contact. At worst, this may cause collapse in those with a severe allergic reaction. Skin irritation may continue for up to two weeks.