Alcyonacea

Order Alcyonacea (commonly known as Soft Corals)

Scientific classification
Kingdom:	Animalia
Phylum:	Cnidaria
Class:	Anthozoa
Subclass:	Octocorallia
Order:	Alcyonacea Lamouroux, 1812 [1]

Where seen?
Soft corals are commonly seen on many of our shores. Some resemble flowery bushes, others giant leathery disks. Yet others are tiny and overlooked. They are found growing on boulders and other hard surfaces, as well as among coral rubble and living hard corals on the reef flats.

Features:
Soft corals are colonies of tiny, individual polyps linked to one another. Soft corals can look like branching bushes or trees. They may also be flatter and look like mushrooms. When exposed at low tide, they often flop over and look like a pile of jelly or fried eggs! When submerged, however, they expand into beautiful plant-like forms and some appear 'furry' as the tiny polyps expand.
Soft coral polyps have 8 (or multiple of 8) tentacles that are pinnate (branched or feathery).

Soft support:
Although there are some exceptions, many soft corals don't produce a hard skeleton. Instead in colonial soft corals, the polyps are connected by a shared tissue.

Tiny spikes of calcium carbonate, called sclerites, are embedded in the tissue mass. These sclerites are used to identify soft coral species. In some, the sclerites are far apart resulting in a more floppy soft coral. In others, the sclerites are closer or fused together to form firmer support. The entire tissue mass is covered with a skin and the polyp tentacles emerge through this skin. In some soft corals, the skin can be quite tough and leathery looking, thus these are often called leathery soft corals. Out of water, soft corals may flop over and may look small. But underwater, they expand and spread out to maximise the feeding surface.

What do they eat?
Most soft corals feed on plankton, some also feed on finer particles. Like other cnidarians, soft coral polyps have tentacles with stingers to capture food.

Many soft corals harbour microscopic, single-celled symbiotic algae (zooxanthellae) within their bodies. The algae undergo photosynthesis to produce food from sunlight. The food produced is shared with the host, which in return provides the algae with shelter and minerals.

Role in the habitat:
Some soft corals are homes to tiny animals. Some tiny animals eat soft corals and look just like their much larger prey.

Coral babies:
Soft corals can reproduce asexually: budding of new polyps enlarges the colony. However, they also reproduce sexually. The polyps may produce sperm or eggs. The eggs develop into free-swimming larvae that drift with the plankton before settling down to start a new colonies.

Credit: http://www.wildsingapore.com/wildfacts/cnidaria/coralsoft/coralsoft.htm