Gorgonians

Gorgonian cave

Gorgonians or horny corals form colonies with an axial skeleton.

They have a special internal reinforcing rod of a hard, but flexible protein material, known as gorgonin, in addition to spicules.

Forming long whips and densely branched fans, gorgonians are found growing at right angles to the current, sieving plankton from the water that flows past.

Some gorgonians, usually yellow-brown, contain zooxanthellae and grow in sunny waters but many (such as those pictured right), are self-reliant and grow under ledges and on cave roofs.

Their colourful spicules give them bright red, yellow and lavender colours.

Gorgonians are most often found at moderate depths, around 18-30 metres.