The fins are the swimming organs of the fish, which are divided into dorsal, pectoral, ventral, anal, caudal, and adipose fins. Fish have evolved a variety of fins through natural selection, and the mechanism of action of different fins renders a variety of movement patterns.

The dorsal fin, located in the dorsal midline of aquatic vertebrates, is the structure supported by the fins that grow on the back.

Pectoral fins, located behind the right and left gill pores. The main function is to move the body forward and to control direction or act as "brakes" during travel.

Ventral fins, the location of the ventral fins varies with different fishes. In cartilaginous fishes, the ventral fins are usually located on both sides of the cloacal aperture.

The anal fin, the anal fin is located in the midline of the abdomen, behind the anus.

The caudal fin, a type of median fin in fish and some other vertebrates, is located at the end of the tail.

Adipose fin, positioned between the dorsal and caudal fins.