of the fish's stroke is the fin used by the fish's stroke. The fin is its appendage, consisting mainly of the basilar and rays, of which the rays are divided into two types, one is unsegmented and the other is segmented or branched. Usually there are five kinds of fins in fish, namely pectoral fin, pelvic fin, dorsal fin, anal fin and caudal fin, but some fish have special fat fins, and some fish have partial fins that have been degenerated or deformed.
of each fin? 1. Pectoral fin: The pectoral fin is located a little below the head of the fish. It is like the forelimb of a terrestrial animal. It can not only provide some power for it to move forward when the tail fin is not moving, but also turn by swinging the pectoral fin on one side. In addition, when swimming at high speed, the pectoral fins can also play the role of braking.
2. Pelvic Fin: The pelvic fin is similar to the hind limbs of terrestrial animals. It can coordinate the dorsal fin and anal fin to maintain balance. At the same time, it can also play an auxiliary role when the fish rises and falls. It is worth mentioning that the position of the pelvic fins is not fixed, some grow on both sides of the cloaca, some grow in front of the pectoral fins, and some are located between the two gills.
3. Dorsal fin: The dorsal fin grows on the back of the fish and can play a role in maintaining balance. But for some fish, the dorsal fin is the source of power, such as hairtail, electric eel, conger eel and so on, they can move forward through the dorsal fin.
4. Anal Fin: The anal fin is located in the midline of the abdomen of the fish body. It is mainly responsible for maintaining balance and coordinating swimming. Most fish have only one anal fin; cod have two.
5. Caudal fin: The caudal fin is the most important fin of a fish. It is located at the tail. It can provide forward power by swinging from side to side. At the same time, it can control the direction of swimming. If the caudal fin is lost, the fish cannot turn.
