Gorgonian Sea Fan

Photo: Julia Lewis DVM · CC BY-NC-ND

Enormous gorgonian fans exceeding two meters in diameter grow perpendicular to the prevailing current on Banda Besar Wall, filtering plankton with thousands of tiny polyps that extend their feeding tentacles when flow is strongest. These slow-growing invertebrates provide structural habitat for pygmy seahorses, longnose hawkfish, and crinoids, making each individual fan a microhabitat supporting dozens of species. Their age — some large specimens are estimated at over 100 years old — makes them irreplaceable anchors of biodiversity on the wall.