Sea fan

부채산호

A coral relative with flat, fan-shaped branches that is really a colony of countless tiny polyps. It stands facing the current so passing plankton drift into its grasp. It anchors firmly to rock and stays in one place for life.

See it on the 3D globe →

At a glance

Class: Jellyfish & corals
Diet: Filter feeder
Habitat: coral reefs

Quick answers

Where does the Sea fan live?

It lives in coral reefs of the Atlantic, Pacific and Indian oceans.

What does the Sea fan eat?

Its diet: filter feeder.

A sea fan looks like a flat, lacy fan growing on the reef, but it is really a colony of thousands of tiny animals called polyps. It is a relative of corals and belongs to a group called gorgonians. The purple common sea fan, Gorgonia ventalina, lives in the western Atlantic and the Caribbean, and sea fans of other kinds live in oceans around the world.

A colony can grow up to 1.5 metres tall, though only a few centimetres thick. It is whitish, yellow or pale purple, and the main branches are often purple. Roughly 500 species of gorgonians are known from tropical to polar seas and the deep sea.

A fan that catches food

The fan sits upright at right angles to the water current, like a net across a stream. Each polyp reaches out eight tentacles to catch tiny drifting plankton. It also has partner algae living in its tissues that use sunlight to make food for the coral. Sea fans stay fixed in one place all their life, anchored to rock.

Tough and sometimes sick

The skeleton is made of calcite and a flexible protein called gorgonin, with tiny hard pieces that predators find unpleasant. A sea snail called Tritonia hamnerorum is not put off by this, and it keeps the chemical to protect itself. Sea fans can get diseases, such as a fungus that causes patches and purple spots, especially in stressed or low-salt water.

Fun facts

A sea fan grows across the current so its tiny polyps can catch passing plankton.
One fan is a colony of countless tiny polyps.
It grows across the current to catch plankton.
A colony can reach 1.5 metres tall but is only a few centimetres thick.
About 500 kinds of gorgonians live in the world's oceans.