Coho have white gums, black tongues and a few spots on the upper portion of their bodies and silver-colored tails. They have a wide tail base. the cleithrum (collar of the fish, under the gillcover) is distinctly blue peppered or mottled. Bright silver with a metalic blue dorsal surface, Coho usually live for three years and grow rapidly in their final year. They weigh between 1.3 kg and 14 kg (3 - 31 pounds) and grow up to 98 centimetres (38 inches) in length. In the Strait of Georgia from April to early June, small Coho passing from the grilse stage to maturity are called bluebacks.