Species guide

Salmon identification: tell the species apart

To identify salmon, check the inside of the mouth, the spots on the back and tail, and the shape of the tail base. Those three field marks separate Chinook, coho, sockeye, pink, and chum salmon in seconds - this guide (and the chart below) shows you exactly what to look for.

Salmon ID in three checks

Mouth and gums - black mouth with black gums = Chinook; black mouth with white gum line = coho; white mouth = sockeye, pink, or chum.
Spots - small spots on back and whole tail = Chinook; upper tail lobe only = coho; large oval blotches = pink; no distinct spots = sockeye and chum.
Body and tail - slender tail base with faint vertical bars = chum; hump on spawning males = pink; big-eyed, toothless look = sockeye.

The five Pacific salmon, one by one

Chinook (king) salmon

Oncorhynchus tshawytscha. The largest salmon, commonly 10–25 lb and capable of far more. Field marks: a black mouth with black gums, small irregular spots across the back and on both lobes of the tail, and a thick, powerful body. Ocean fish are silvery with a purple-green back; spawners turn olive-brown to maroon.

Coho (silver) salmon

Oncorhynchus kisutch. The Chinook lookalike, typically 6–12 lb. Field marks: a black mouth with a white gum line, spots on the back but usually only on the upper lobe of the tail, and a squarish, lightly forked tail. Spawning males develop a strong kype and brick-red flanks.

Sockeye (red) salmon

Oncorhynchus nerka. Slim and toothy-less in appearance, usually 4–8 lb. Field marks: almost no spots on back or tail, a bright silver-blue ocean coloration, prominent golden eyes, and fine, numerous gill rakers. Spawning fish are unmistakable: crimson bodies with green heads.

Pink (humpy) salmon

Oncorhynchus gorbuscha. The smallest and most numerous, typically 3–5 lb. Field marks: large oval blotches on both tail lobes and back, very small scales, and a thin tail wrist. Spawning males grow the namesake hump. Runs are strongly two-year cyclical.

Chum (dog) salmon

Oncorhynchus keta. Often 8–15 lb. Field marks: no distinct spots, a white mouth, a narrow tail base, and silver streaks in the tail rays. Spawning fish show bold purple-green vertical bars ("calico" pattern), and males grow large canine-like teeth.

Atlantic salmon

Salmo salar - a different genus, native to the North Atlantic. Field marks: black X- or Y-shaped spots above the lateral line, a tail that is almost always spot-free, a slender tail wrist, and a slightly forked tail. Most Atlantic salmon seen today are farm-raised.

Salmon species identification chart

Compare the key field marks side by side. Sizes are typical adult ranges; individual fish vary.

Salmon species identification chart (ocean coloration)
Species	Mouth & gums	Spots	Tail	Typical size	Other marks
Chinook (king)	Black mouth, black gums	Small spots on back and both tail lobes	Moderately forked	10–25 lb+	Largest species; thick body
Coho (silver)	Black mouth, white gum line	Back and upper tail lobe only	Square, lightly forked	6–12 lb	Wide tail wrist; strong kype when spawning
Sockeye (red)	White mouth	None distinct	Slightly forked	4–8 lb	Prominent eyes; crimson body when spawning
Pink (humpy)	White mouth	Large oval blotches on back and tail	Blotched, forked	3–5 lb	Tiny scales; males hump when spawning
Chum (dog)	White mouth	None distinct	Silver streaks in rays; narrow base	8–15 lb	Calico bars when spawning; large teeth
Atlantic	White-gray mouth	X/Y-shaped spots on body, none on tail	Slightly forked, spot-free	8–12 lb	Different genus; slender tail wrist

Tip: photograph the open mouth and the tail - those two shots contain almost every mark in this chart.

Salmon or trout? The anal fin test

Salmon and trout share waters and body plans, and steelhead (sea-run rainbow trout) are silver like salmon. The most reliable separator is the anal fin: Pacific salmon have a long anal fin base with roughly 13–19 rays; trout and char have a short one with about 12 or fewer. Add the tail: salmon tails are usually more forked, trout tails squarer. For the full trout side of the story, see our trout identification guide.

Ocean phase versus spawning phase

Every chart above describes ocean-bright fish. Once salmon enter rivers to spawn, they stop feeding and transform: colors shift to reds, greens, and bars; jaws hook; humps grow. A September river fish can look like a different animal than the same fish in July. When in doubt, lean on the structural marks - mouth color, spot pattern, tail shape - which persist through the transformation.

Identify salmon with a photo

The Fish Identifier app reads the same field marks from a clear side photo and suggests the species with the traits it recognized, typical size, habitat, and season. It is a quick second opinion on the bank - and the saved photo lets you re-check the ID at home. For neighboring species, see the freshwater guide and saltwater guide.

FAQ

Salmon identification FAQ

How do I identify a salmon quickly?

Check three marks in order: the inside of the mouth, the spots on the back and tail, and the tail base. A black mouth with black gums points to Chinook; a black mouth with a white gum line points to coho; large oval blotches on the tail point to pink salmon; no spots plus a slender tail base with faint bars points to chum; nearly spotless silver-blue with prominent eyes points to sockeye.

What is the difference between Chinook and coho salmon?

Look inside the mouth. A Chinook (king) has a black mouth including black gums, spots on both lobes of the tail, and a thicker body. A coho (silver) has a black mouth with a white or gray gum line, spots usually only on the upper tail lobe, and a squarer tail. Chinook also grow considerably larger on average.

How can I tell a salmon from a trout?

The anal fin is the classic separator: Pacific salmon have a longer anal fin base with roughly 13 to 19 rays, while trout have a shorter one with about 12 or fewer rays. Salmon also tend to have a more deeply forked tail and a slimmer wrist at the tail base. Steelhead (sea-run rainbow trout) look salmon-like but keep the trout-style short anal fin and a square tail with radiating spots.

Why do salmon change color in rivers?

When salmon leave the ocean to spawn, hormones transform their bodies: silver flanks turn red, olive, or striped, males grow hooked jaws (kypes) and, in pink salmon, a hump. That is why the same fish can look completely different in July at sea and in September upriver. Identification charts, including ours, therefore show both ocean and spawning phases.

Can a fish identifier app recognize salmon species?

Yes. A clear side photo shows an app the same marks you would check by eye: spot pattern, tail shape, and body proportions. Mouth and gum color can be hard to see in a photo, so for lookalike cases such as Chinook versus coho it helps to photograph the open mouth too and compare the app’s suggested traits with the fish.

Where do Atlantic salmon fit in?

Atlantic salmon (Salmo salar) are a different genus from the Pacific species. They show black X- or Y-shaped spots on the body, almost never spots on the tail, and a slimmer tail base. Wild Atlantics are rare in most fisheries; most Atlantic salmon encountered today are farmed fish.