The coho salmon, also know as the silver salmon can be distinguished by the fine dark spots on the back and upper lobe of the tail fin, the long anal fin and gray gums.
Coho feed primarily on alewives, smelt, and other small fish.
After spawning is completed they die. The average mature fall coho salmon will weight 5 to 6 pounds before spawning. Because this species dies after spawning and the recruitment from stream spawning is very limited, an annual stocking program is necessary. In Illinois coho are reared in an accelerated fashion and in 6 months are stocked as 5-6 inch long fish in the spring. Due to the lack of clean, cool streams salmon do not reproduce in Illinois.