Types of fins

a) Dorsal Fin:

• This type of fin is located on the top or back of the fish which helps the fish in quick turns or stops.
• It also helps the fish against rolling. In fish, there are three distinct dorsal fins such as proximal, central or middle, and distal dorsal fins.
• Some fish have two dorsal fins where the central and distal fins are combined.

b) Pelvic Fin:

• In fishes, a pair of pelvic fins are present which are located ventrally below and behind the pectoral fins.
• In some fishes, they are situated in front of the pectoral fins (Cod family). This type of fin helps in stability and slowing down the fish.
• Generally, fish use pelvic fins for moving upwards and downwards in the water.

c) Anal Fin:

• The Anal fin is also known as the cloacal fin which is located on the ventral side just behind the anus.
• It supports the dorsal fin and stabilizes the fish during swimming and controls the rolling motion.

d) Pectoral Fin:

• Pectoral fins are located on both sides usually just behind the operculum. It is homologous to the tetrapod`s forelimbs.
• It provides support during swimming. It creates dynamic lifting force and also helps the fish to turn left or right.

e) Adipose Fin:

• They are soft fins located between the dorsal and caudal fins, usually very near to the caudal fin.
• It is mainly found in Salmonidae, Characins, and catfishes. This type of fin helps to navigate the fish in rough water.

f) Caudal Fin:

• The caudal fin is the primary appendage which is used for locomotion in many fishes.
• The caudal fin is also known as a tail fin or a median fin which is usually homocercal or heterocercal.
• Generally, it is a vertically expanded structure which is located at the caudal end of the body. The base of the caudal fin is known as the caudal peduncle with strong swimming muscles.
• In general, the caudal fin acts like a propeller while the caudal peduncle functions as a motor.