Fins come in all shapes and sizes and have all sorts of uses. Check it out:
A freshwater angelfish's long, curved fins are beautiful. But they also help the angelfish stay safe. They blend right in with the long leaves of plants growing in the fish's river home. Angelfish? What angelfish?
Photo: © Jeff Kubina / Wikimedia Commons
The flying fish has big side fins that it uses like wings. First it swims very fast toward the surface, then it "flies" out of the water with the fins spread. Flying fish have been known to glide through the air as far as two football fields. It's a great trick to escape predators.
A sailfish has a large dorsal (back) fin called a "sail." The sail can cover the entire length of the fish's back. The sailfish raises its sail when it's threatened or under attack and that makes itself look bigger. Otherwise, the fish keeps its sail folded down and to the side when swimming along.