Wild About Illinois Fishes!

Family Anguillidae - Freshwater Eel

Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Anguilliformes - Eels may be found in fresh and salt water. The head is wedge-shaped and has a hard mouth. There are no pelvic fins on the long, thin body.
Family: Anguillidae - Eels have no pelvic fins. The scales on the body are very tiny. The dorsal, caudal and anal fins are merged into one continuous fin. These snaked-shaped fishes have an interesting life cycle. Adults migrate to an area in the Atlantic Ocean to reproduce and die. The larva that hatches from the fertilized egg makes a one-year trip to the shores of North America. After maturing, males remain along the coast, and females move upstream where they may remain for 15 years. The American eel is the only species of freshwater eel found in North America.

American eel (Anguilla rostrata)
Photo © Victor Vrbovsky/Engbretson Underwater Photography

Features and Behaviors

FEATURES

The American eel grows to a maximum length of 60 inches. Its average size is two and one-half pounds in weight and 16 to 33 inches in length. The female is larger than the male. The body is snakelike with no pelvic fins. The dorsal fin covers more than half the length of the body and is connected to the tail fin which in turn connects to the anal fin. The head is pointed, and the lower jaw extends beyond the upper jaw. The body is yellow or brown on the back and sides with a yellow or white belly. The scales are tiny.

BEHAVIORS

American eel adults spend five to 20 years in fresh water before migrating to the sea to breed. Males tend to stay near the coast, while females swim far inland until their movement is blocked by a dam or other object. Any eel found naturally in Illinois is a female. The eggs are laid in the Sargasso Sea of the Atlantic Ocean near Cuba. Larval eels live in the ocean for about a year before transforming to the elver stage and traveling to fresh water.