Knitted in the round this is an easy pattern if you already know how to knit stranded colorwork and this pattern assumes that you do know how to knit stranded colorwork. If you have not knitted stranded colorwork before then this is an experienced level pattern.

Instructions are given for head sizes 18” (46 cm), 21” (53 cm), and 23” (58 cm). These correspond to child, small adult and medium-large adult sizes.

Fingering weight yarn.
WC: (water color), FC: (fish color) The sample was knitted with Happy Sheep Magic Sock Wool and Knit Picks Hawthorne.
Size 18” (46 cm), WC 75 yds (69 m), FC 39 yds (36 m)
Size 21” (53 cm), WC 101 yds (76 m), FC 38 yds (56 m)
Size 23” (58 cm), WC 118 yds (108 m), FC 50 yds (46 m)

From the Smithsonian Magazine: Adult salmon live in the cold ocean, and both warming and acidification, now occurring because of global warming, are bad news for them. They eat and grow for up to four years, and then begin migrating back to their birth stream, fighting their way upstream to spawn. The female digs a nesting pocket in the gravel streambed to lay her eggs, while the male, fighting other males for the privilege, fertilizes them, after which they both die.
The carcasses of spawned-out salmon bring a load of nutriments from the ocean back to otherwise nutrient-poor rivers. Bears, foxes, wolves, eagles, wrens and ravens feed on salmon flesh. Even salmon fry feed on the flesh of their parent generation. And salmon are sacred to many Indigenous people.
As well as navigational improvements—removing the snags the salmon need to provide pools for resting, industrial capitalism and its enterprises have wreaked havoc on the wild salmon of the Pacific Northwest. Loggers built splash dams, blocking a stream to build up a force of water, releasing it each day or week to shoot logs (and the streambed) downstream. Logging roads eroded hills and caused landslides; silt buried spawning gravel. Canneries wasted fish, driving salmon runs to extinction. Sawmills clogged streams with sawdust. Farmers and householders cleared land down to the water’s edge, and streams silted up and warmed up. Industry fouled the waters. Dams provided inadequate fish ladders or no fish ladders. The first hatchery was built in 1895, and early hatchery managers ignored fish biology even after it was understood.
In the Pacific Northwest, 19 populations of wild salmon and steelhead are listed as threatened under the Endangered Species Act. Salmon have already gone extinct in 40 percent of their historical range.