Identifying Fish Fins

To be able identify and discuss fish, it is helpful to know all the types of fish fins. It makes descriptions much easier, and there really aren't that many. Here are the eight types of fish fins:

  • Dorsal fins are found on the back of the fish. There may be up to three of them. The fish uses this fin for balance in the water and sudden movements.
  • Caudal fins are also known as tail fins. This is what we refer to as the fish's tail.
  • Anal fins are on the ventral (bottom) surface of the fish, behind the anus. Fish use these for stability while swimming.
  • Pectoral fins are located on each side of the fish, around where the head meets the body. These are often thought of as the fish's "arms".
  • Pelvic fins are located on each side of the fish, near it's bottom middle. These help the fish go up and down as well as turn sharply in the water.
  • Adipose fins are soft fins found between the dorsal and caudal fins, usually closer to the caudal fin.
  • Caudal keels are small horizontal fins just forward the caudal fin on each side of the fish. You'll find these on faster swimming fish.
  • Finlets are small fins that look like ridges along the top and bottom of the fish, behind the dorsal and anal fins.

[Fish finsClick to enlarge][]

Of course, not all fish have every type of fin. Refer back to this page if you come across a fin you don't know while reading our fish identification series.

[Fish finsClick to enlarge]: