A dorsal fin is a type of a fin that is located on the backs of fishes. It is mainly found on the backs of Dolphins, Whales and Porpoises. The dorsal fin was also found on the back of the extinct Ichthyosaurs. The main purpose of the dorsal fin is to keep the fishes stable and help them in making sudden turns. With time and evolution passing by many of the fishes have developed dorsal fins that have protective functions like venom and spines on them. Dorsal fins come in various shapes and sizes, depending on the body of the fish.
Certain cat fishes can lock the front ray of their dorsal fin in a position that can block them from being attacked by other predators. Doing this also helps these fishes into hiding into certain crevices.
Certain cat fishes can lock the front ray of their dorsal fin in a position that can block them from being attacked by other predators. Doing this also helps these fishes into hiding into certain crevices.