Broccoli soft coral

The broccoli coral (Litophyton arboreum) needs no explanation for its name: the grey-green, bush-like branching colony with its florets is the spitting image of broccoli. Its soft trunk and branches stand inflated with water – when the current picks up or the colony is disturbed, it contracts and "deflates" to half its size like a punctured balloon. The same coral can be a plump little tree in the morning and a limp bundle by afternoon.

It belongs to the soft corals, meaning it has no hard limestone skeleton: its tissues are stiffened by tiny calcareous needles called sclerites. It draws energy partly from symbiotic algae living in its tissues and partly from plankton filtered out of the water. Against predators it fights with a chemical arsenal, producing compounds that researchers are studying in the search for antifungal and anticancer agents – the reef is quite literally a floating pharmacy.

It is very common around Hurghada: you meet it on reef slopes, plateaus and shallow coral gardens alike, so snorkelers can recognise it too. Whole "broccoli groves" often grow side by side with clouds of glassfish between them – one of the most rewarding photo subjects. Soft corals are fragile: one bad fin kick erases years of growth, so keep your distance and know where your gear is dangling.