"Fan corals" refers to a type of coral that looks like a fan. It has a flat shape with many branches spreading out like a handheld fan. Full definition
Fan coral branches tossed against a linear, watery background bring the beauty of an underwater garden to your bedroom. (steinmart.com)
These sea fans which are pastel in color are perhaps the most beautifully colored of all the sea fan corals found in Thailand. (DiveAdventuresAsia.com)
Beautiful fan coral dances lazily as... (ramons.com)