bony skin-covered spines or rays protruding from the body of a fish or aquatic mammal
AI overview
A fin is a bony, skin-covered structure that sticks out from a fish or aquatic mammal's body. Fins are important because they help these animals move, steer, and balance in the water.
AI-generated from the Wikipedia summary — may contain errors.
Article
Ray fins on a teleost fish, Hector's lanternfish
(1) pectoral fins (paired), (2) pelvic fins (paired), (3) dorsal fin, (4) adipose fin, (5) anal fin, (6) caudal (tail) fin