The official state fish of Washington is the steelhead trout. These trout are the same species as rainbow trout but live in marine environments throughout their adulthood.
Steelhead range through the northern Pacific Ocean, from east Asia down along the North American coast. They hatch in freshwater then travel into the sea upon reaching adulthood, only returning to freshwater to reproduce. Washington's steelheads spawn in the same freshwaters where they grew up.
Although they are called trout, they are a type of salmon. However, unlike other species of salmon, steelhead can spawn multiple times over the course of years.
Rainbow trout and steelhead are the same species, but rainbow trout live their entire lives in freshwater rather than returning to the sea as adults.