One of seven species of the genus Oncorhynchus native to North America, coho salmon are found in most of the coastal streams and rivers of British Columbia. Interior Fraser River coho salmon spend 18 months at sea before returning to freshwater to spawn. The Interior Fraser River watershed includes systems within the Fraser River watershed upstream of Hells Gate in the Fraser River canyon in British Columbia.

Adult coho salmon have silvery sides and metallic blue backs with irregular black spots. Spawning males have bright red sides, and bright green backs and heads, with darker colouration on their bellies. The fish have hooked jaws and sharp teeth. Young coho salmon are aggressive, territorial and often vibrantly coloured, with a large orange anal fin edged in black and white.