Sea fan

Sea fans are soft corals that look much like underwater plants. They are distinguished by the possession of spicules that are made of a horny substance called gorgonin from which they derive structural support. They are often called Gorgonians (from gorgonin) and some taxonomic systems place them in the Order Gorgonacea.

All of these animals produce specialized stinging cells, and have no organs. According to the evolutionists, they were the first group to have a gastrovascular cavity. Sea fans are members of the class called Class Anthozoa. Their bodies are divided into many chambers by septa, also known as partitions. There are about 500 species of Gorgonians (sea fans) that usually grow in the shallow currents of the oceans. They get to be up to 6 feet high and 5 feet wide. Most sea fans are nocturnal; they only extend their polyps during the nighttime. They eat plankton and they also need strong currents to carry food to them. 

Anatomy
The main structural skeleton of a sea fan colony is formed from a flexible, horny substance called gorgonin. They have a structural skeleton that is erect, flattened, branching colonies in ocean waters. They have eight feathery tentacles to feed on plankton and other organisms with living polyps covering the surface. 

Reproduction
Soft corals, such as sea fans, reproduce both sexually and asexually and have several methods of doing either. Sea fans have separate male and female organs, also known as hermaphroditic. Most sea fans reproduce by spewing massive quantities of gametes (eggs and sperm) into the open ocean water.

Larvae that are not consumed by filter feeders plant themselves in the mud or sand and form a new colony of sea fans. The female sea fan produces so many eggs that it doesn't matter if one is eaten because most will form new colonies. Because the offspring are in the water from the time they are fertilized, there is a good chance that the new sea fans will be carried far from their parent colonies by ocean currents. As a result, when they broadcast all their eggs and sperm making new polyps, Sea fans and many other soft corals species are often found in oceans all over the world. Some colonies settle very close to their mother colonies or where they were released, this enables a fast colonial growth.

Ecology
Sea Fans are found worldwide in tropical seas. They are mostly found in reefs, attached to rocks, or at the bottom of seas. They also live in the Atlantic ocean and from Bermuda south to Curacao and the West Indies. Sea fans usually grow across the current so that their polyps can spread out their tentacles to form a net for catching plants or (plankton.) Sea fans can either be solitary or colonial. When in a colony, the polyps are held together by living tissue, the coenenchyme, and the sea fans gastrovascular cavities are held together by canals or tubes. They anchor themselves in mud or sand instead of attaching to hard surfaces. Most sea fans, if not all are filter feeders.