Sea run sockeye have dark blue backs with few spots and bright silver sides. When they enter fresh water after a typical 2 years at sea, both males and females develop bright red bodies and green heads. The males’ bodies become laterally compressed, a hump grows behind the head, the jaws become hooked, and sharp canine teeth appear.
Sockeye fry, after emerging from the gravel, migrate to freshwater lakes, where they spend 1 to 2 years before heading out to sea. Some populations, called kokanee, spend their entire lives in freshwater lakes.