Wild About Illinois Fishes!

Family Osmeridae - Smelt Family [nonnative]

Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Salmoniformes
Family: Osmeridae - Smelts are small, slender fishes with a large mouth, cycloid scales, a lateral line, an adipose fin and no spines in the fins. They eat crustaceans. The rainbow smelt became established in Lake Michigan in the 1930s.

rainbow smelt (Osmerus mordax) [nonnative]
Photo © Sean Landsman/Engbretson Underwater Photography

Features and Behaviors

FEATURES

The rainbow smelt has a very large mouth with jaws that reach to the back edge of each eye. Big teeth are present on the tongue and the roof of the mouth. The body is long and slender, and an adipose fin is present. The back is dark green. The sides are silver to blue. The front edge of the pelvic fins is in line with or slightly behind the front edge of the dorsal fin. Mature rainbow smelt are seven to 10 inches long.

BEHAVIORS

Rainbow smelt live in water 15 to 200 feet deep and often within a mile of shore. They migrate in groups into tributary streams to spawn in late winter and spring when the correct water temperature occurs. This species eats crustaceans, insect larvae and small fishes.