The dorsal fin provides stability while swimming. It may also regulate body temperature in warm-blooded animals such as the dolphin. The dorsal fin is located at the top of the animal.
Fins are made of stiff rays covered by skin. Fins known as spines are bony, stiff and unjointed, but most fins are very flexible and function as swimming aids. Several different kinds of fins exist, and the number of fins varies according to the type of fish. Pectoral fins are located on the sides of the body. They help with starting and stopping and side-to-side motion. In some animals, they also aid in the reproduction process by providing a method to clasp the opposite sex. The caudal fin is called the tail fin, which is the main propeller for the body. The anal and adipose fins aid in stability.
Stability provided by the dorsal fin is very important. As a result of genetic engineering, the lionhead goldfish has no dorsal fin. This affects control and agility in the water and can be a serious handicap in the wild. At rest, these fish have a tendency to roll to the side. They are slower and less efficient than normal goldfish. All normal fish have dorsal fins.