Fish locomotion

Fish move through the water in a few different ways, but the most common is by using their tail fin to propel themselves forward. The tail fin is called the caudal fin, and it's shaped like a fan, with a top and a bottom edge.

When a fish wants to move forward, it first curves its body into a "C" shape, so that the tail fin is facing the direction it wants to go. Then, it uses special muscles to move the tail fin from side to side, pushing against the water and propelling the fish forward.

Some fish also use their pectoral fins, which are the ones on their sides near the front of their body, to help them swim. They can flap these fins to help them turn or swim up and down.

Overall, fish use a combination of muscles and fins to move through the water, and it's quite amazing to watch!