Function of fin

• Generally, the pectoral fins help a fish for turning.
• Some bony fishes use their pectoral fins to help them rest on the bottom or on reef areas (e.g. Cirrhitichthys).
• Mudskippers (Periophthalmidae family) use pectoral fins for supporting themselves on land.
• Flying fish (Exocoetidae family) use their long pectoral fins for gliding over the water.
• Pectoral fins of some bottom-residence fishes such as threadfins (Polynemidae) bear touch receptors and taste buds which help to trace food.
• Pelvic fins help the fish stability in the water.
• Pelvic fins of some fishes such as clingfishes (family Gobiesocidae) use as sucking appendage, which helps a fish hold on to stationary objects on the ocean bottom.
• Most of the bony fishes use their dorsal fin for sudden direction changes.
• Dorsal fins act as a ‘keel’ for keeping the fish stable in the water.
• Some angelfishes (Lophiiformes) use their dorsal fin as a lure which helps to attract the prey.
• The modified dorsal fin of some fishes (Echeneidae) use as a sucking disc.
• African knife fish (Gymnarchus niloticus) use its dorsal fin to move forward or backward by creating undulating.
• Most of the bony fish use their caudal fins for propulsion.
• Lunate caudal fins are characteristic features of fast swimmers such as tunas. They use it for maintaining rapid speed for long duration..
• Anal fins make stability and anal fins of some bony fishes help in reproduction.
• Sea Robin fish use their pelvic fin for walking along the substrate.
• Some fishes such as Freshwater butterflyfish (Pantodon buchholzi) use their pelvic fins for gliding.
• Sea Robins use their pectoral fin for gliding around in the currents.
• Lionfish and other scorpionfish have dorsal fins with hollow venomous spines which are used for self-defense.