The caudal fin is the most important part of the fish. It can provide the power for the fish to move forward and determine the direction of swimming. If the tail fin is missing, the fish can't turn. According to the shape of fish, they can be divided into four categories, namely, round tail fin, oblique tail fin, normal tail fin and original tail fin.
For fish, pectoral fins also play a more important role, on the one hand, it can maintain balance, on the other hand, it can also play a role in slowing down and braking when swimming at high speed. Fish without pectoral fins are easy to sway from side to side. The pectoral fins are usually located behind the operculum and on its chest.
The role of pelvic fins is only one, that is to maintain balance, and like pectoral fins, if lost, it will sway from side to side. In addition, when the fish in the rise and fall and when turning, can also play a role in assisting. Interestingly, the position of the pelvic fins is not always on the abdomen. Some grow in front of the pectoral fins, while others grow in the throat between the gill covers.
Dorsal fin allows the fish to stand on its side, if it does not, the fish will roll over. For some special fish, the dorsal fin can also play an auxiliary role in movement, such as the hippocampus is relying on the dorsal fin to move forward.
For fish, although the anal fin can also play a role in maintaining balance, it is more to coordinate other fins when the fish swims, without this part, the body will appear slightly shaking.
