Gorgonian

As sea fans, gorgonians or sea fans ( Ez gorgonian; rarely Gorgonia ) are referred to a group of similar corals of the subclass Octocorallia. The gorgonians do not form a monophyletic unit, but should be viewed as a group only because of their similar growth form and the skeleton of the horn-like substance Gorgon. They are summarized in two taxonomically recognized suborders ( Calcaxonia and Holaxonia ) and a group ( Scleraxonia ).

All sea fans, as all of their relatives from the subclass Alcyonaria, polyps with eight pinnate tentacles. Horn coral live in all oceans from shallow waters to the deep sea. A photo of the Titanic in 4000 meters depth shows a gorgonian that grows on the wreck. The coral reefs of the Caribbean are dominated by sea fans, because they are relatively abundant there. Most living in the Caribbean species live in an endosymbiosis with unicellular symbiotic algae ( zooxanthellae ).