Columnar porites

Columnar porites (Porites nodifera) colonies grow not domes but tightly packed pillars, from finger- to thigh-thick – a large colony looks like a city of miniature organ pipes. The colour is yellow-brown, mustard or greenish, and the surface feels velvet-smooth thanks to millimetre-sized polyps. In shallow, sheltered bays these pillar forests often carpet whole hectares and define the underwater landscape.

This species is a true Red Sea specialist: it thrives in hot, salty, shallow lagoons where most corals would give up. Its partnership with zooxanthellae algae and its slow, persistent growth make it remarkably tough. Between the pillars a sheltered labyrinth forms that works as a fish nursery: juvenile parrotfish, damselfish and cardinalfish shoals hide in the passages, and at night the polyps stretch out their tentacles to hunt plankton.

Around Hurghada you meet it most often on the shallow coastal reefs and along the edges of sandy lagoons – whole pillar forests grow in the bay of Abu Hashish and in the coral garden of Shaab Sabina, and you can admire them while snorkeling. In water this shallow the rule matters more than ever: never stand on coral, not even "just for a second" – the tops of the pillars are living tissue that dies where it is touched.