Is a fish's tail fin a fin or a tail?

The “tail fin” is called the Caudal Fin. It is a fin. What the the fin is attached to is called the Caudal Peduncle. The “tail” of the fish usually includes everything in the posterior end of the fish (see shark pic). read more

The “tail fin” is called the Caudal Fin. It is a fin. What the the fin is attached to is called the Caudal Peduncle. The “tail” of the fish usually includes everything in the posterior end of the fish (see shark pic). This photo gives a general classification of fish (Osteichthyes) fins plus some extra anatomy. read more

Fin rot's a condition whereby bacteria attack a fish's fin or tail. Fin rot almost always occurs as a secondary infection. This means the bacteria that cause fin rot, which are everywhere, can cause infection only if the fish is already sick or injured. read more

Apart from the tail or caudal fin, fish fins have no direct connection with the spine and are supported only by muscles. Their principal function is to help the fish swim. Fins located in different places on the fish serve different purposes such as moving forward, turning, keeping an upright position or stopping. read more