sea fan

any of several gorgonians with the axial skeleton formed into a fanlike structure; esp., a horny coral (Gorgonia flabellum) of the West Indies and Florida Keys

See sea fan in American Heritage Dictionary 4

noun
Any of various yellowish to reddish fan-shaped corals of the genus Gorgonia, especially G. flabellum, of coastal waters of Florida and the West Indies.
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