American Eel

freshwater fish · catadromous · slimy · mysterious

Snake-like shape. American eels have long, supple bodies that look more like snakes than typical fish, with a continuous fin running along their back and belly instead of separate fins like most fish have.

Slimy but scaled. Even though eels are covered in a slippery mucus layer that makes them look naked and slippery, they actually have tiny scales underneath, so they're not quite as bare as they appear.

Color from their home. Eels that live in clear water tend to be lighter colored, while eels from dark, tannic streams are often darker, so their color actually tells you something about where they come from.

Missing pelvic fins. Unlike most fish, American eels don't have pelvic fins at all, but they do have small pectoral fins near their head that help them move through the water.

Ancient fish family. American eels belong to a very old group of fish called elopomorphs that have been around since ancient times, making them living ancestors of many modern fish species.