Soft CoralsAlcyonacea

Soft corals are colonial marine invertebrates with polyps possessing eight pinnate (feathery) tentacles. Lacking a rigid external calcium carbonate skeleton, their support comes from internal microscopic calcareous sclerites and hydrostatic pressure, resulting in a fleshy, pliable texture. Colonies display diverse forms, including encrusting mats, massive lobes, branching structures, or whip-like growth, often exceeding a meter in diameter or height. Individual polyps typically measure 1-5 mm across. Colors range from muted browns and greens to bright yellows, pinks, and purples. The order name, Alcyonacea, references the mythical Halcyon bird, believed to nest during periods of calm seas when these corals were thought to appear.

Soft corals thrive on reef slopes, walls, and sheltered areas, occurring from shallow waters down to 40 meters (130 ft). They feed by filtering zooplankton from water currents. Most species also host photosynthetic symbiotic algae (zooxanthellae) within their tissues, supplementing their diet. Many retract their polyps fully into the colony during daylight hours, extending them at night to feed. They are a common and prominent feature of 🌊 Red Sea reefs.