Coho are swift, active fish.
When mature in the late fall, they weight up to 14 kg, although their average weight is between 2.7 and 5.4 kg. Next to pinks, they probably have the most consistent life history of west coast salmon. Juvenile coho are highly adaptable and can have varied life histories. Most stay from one to two years in coastal streams before emigrating seaward as smolts. But other fry are equally at home in lakes or in coastal estuaries.