Finger staghorn coral

The finger staghorn coral (Acropora humilis) is the stocky cousin of the staghorns: instead of slender antlers it grows short, thick, upward-pointing "fingers" that gather into cushion-like colonies of 20–50 centimetres. Its colour runs from cream-yellow through green-brown to violet shades, with branch tips often paler or bluish – a sign of fresh growth. At the top of every finger you can clearly see the large terminal cup typical of Acropora, housing the polyp that leads the growth.

The squat shape is no accident but an engineering solution: A. humilis lives on the reef crest and upper edge, where wave action would simply flatten slender-branched corals. The short, stout fingers break the force of the waves, which is why this species dominates the coral world of the first few metres. Like its relatives it draws energy from the zooxanthellae algae in its tissues and thrives in shallow, light-flooded water – and Red Sea populations rank among the most heat-tolerant corals on Earth, shrugging off summer temperatures that would trigger mass bleaching elsewhere.

Around Hurghada you will meet it on virtually every reef top: the shallow gardens of Shaab Sabina and Gota Abu Ramada, the reef edge of El Fanadir and the plateaus of the Giftun Islands are full of it – snorkeling, you often float within arm's reach (but never reach!). Tiny damselfish and gobies live between the fingers. Its shallow home also makes it the reef's most endangered resident: snorkelers standing or stepping on the reef cause the most damage. Never stand on coral – if you need a rest, find a sand patch or roll onto your back at the surface.