Chinook salmon vs Coho salmon
How to tell them apart, and what follows from getting it right.
Why they get confused
Both are Pacific salmon of similar shape and colour that run the same rivers at overlapping times, and a bright fish fresh from salt water of either species is silver with a dark back and spotted tail. Small chinook and large coho overlap substantially in size, so size settles nothing.
Chinook salmon
Oncorhynchus tshawytscha — Salmonidae
Coho salmon
Oncorhynchus kisutch — Salmonidae
No photograph of Coho salmon has passed identity review yet, so none is shown. FishingHQ publishes a species photograph only once somebody has confirmed the animal in it against the species record’s own diagnostic features.
The differences
Each difference is marked with how far it can be trusted on its own. A single diagnostic character settles the identification; suggestive ones only narrow it.
| Character | Chinook salmon | Coho salmon | Reliability |
|---|---|---|---|
| Gum colour at the base of the teethIdentification | Black gums along the base of the lower jaw — the character that gives the species its 'blackmouth' name in parts of its range. | Grey or white gums with a dark tongue; the gum line does not carry the solid black of a chinook. | Diagnostic on its own |
| Spotting on the tailIdentification | Spots on both lobes of the caudal fin. | Spots usually confined to the upper lobe of the caudal fin, with the lower lobe clean. | Supporting — use with others |
| Maximum sizeSize | The largest Pacific salmon; adults commonly reach weights no other species in the genus approaches. | Substantially smaller at maturity, with far fewer very large individuals. | Suggestive only — varies |
| RangeRange | Native to the North Pacific rim and widely introduced beyond it, including established landlocked populations. | Native to the North Pacific rim with a broadly overlapping but not identical native distribution. | Suggestive only — varies |
| Handling on releaseHandling | A large-bodied fish that must be supported horizontally; its weight makes a vertical lift damaging. | Lighter, but no less vulnerable to a long air exposure after a hard fight in warm water. | Supporting — use with others |
Why it matters
Pacific salmon are managed species by species, and the two are frequently subject to different rules in the same water at the same time. Beyond regulation, the size difference changes how a fish must be supported if it is going back. FishingHQ does not state what any rule is: check the authority for the water you are on.
The full records
This page compares two species. Each of them has a complete record covering biology, behaviour, handling and the evidence behind all of it.
More about chinook salmon
Where it lives, how it is caught, and what else it is confused with.
Similar and related fish
Atlantic salmonThe clearest illustration of what semelparity means: Atlantic salmon can spawn more than once and Pacific salmon cannot. Same family, one irreversible difference.- Coho salmonCongeners that run the same rivers at overlapping times and are separated by the gums: chinook black, coho pale. The rules for them frequently differ, which is why the character is worth learning.
- Northern anchovyIn the California Current anchovy replaces sand lance as the dominant forage item, and the anchovy and sardine regime shift changes what chinook are eating for decades at a time.
- Pacific sand lanceSand lance are a principal prey of chinook in coastal waters, and chinook condition in the north-eastern Pacific tracks sand lance abundance closely.
Rainbow troutCongeners in the genus Oncorhynchus. The difference that matters is that chinook is semelparous and dies after spawning while rainbow trout is not — the same genus, two entirely different life strategies.
Sockeye salmonCongeners with completely different diets: chinook eats fish, sockeye filters plankton with long fine gill rakers. That is why sockeye barely take lures and chinook do.
What these connections rest on (6)
Scientific evidence — 6 connections
Supported by peer-reviewed research or fisheries science. The sources are listed and can be checked.
Atlantic salmon
A life-history comparison naming both binomials, and one that corrects a common assumption that all salmon die after spawning.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: That Oncorhynchus tshawytscha is an anadromous Salmonidae of the North Pacific, distinct from Salmo salar of the North Atlantic.States this directlyPassage read and verified
- NASCO conservation and management of North Atlantic salmon — North Atlantic Salmon Conservation Organization (Government fisheries body)Relied on for: The anadromous life history of Atlantic salmon, including repeat spawning, and its management as distinct river populations.States this directlyCitation checked — the work exists and is described correctly
Coho salmon
A taxonomic and identification comparison naming both binomials, with a practical consequence.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: That Oncorhynchus tshawytscha and Oncorhynchus kisutch are congeners in the genus Oncorhynchus occupying overlapping North Pacific ranges.States this directlyPassage read and verified
Northern anchovy
Recorded diet evidence identifies Engraulis mordax as a food item of this predator at species level. The edge is written at that granularity and no further.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: Food items recorded for this predator, including Engraulis mordax.States this directlyPassage read and verified
- FAO Species Identification Guides for Fishery Purposes and the FAO Species Catalogues — Food and Agriculture Organization of the United Nations (Scientific institute)Relied on for: Species account describing the diet of this predator in the region where Engraulis mordax occurs.Background and mechanism onlyCitation checked — the work exists and is described correctly
Pacific sand lance
Recorded diet evidence identifies Ammodytes personatus as a food item of this predator at species level. The edge is written at that granularity and no further.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: Food items recorded for this predator, including Ammodytes personatus.States this directlyPassage read and verified
- FAO Species Identification Guides for Fishery Purposes and the FAO Species Catalogues — Food and Agriculture Organization of the United Nations (Scientific institute)Relied on for: Species account describing the diet of this predator in the region where Ammodytes personatus occurs.Background and mechanism onlyCitation checked — the work exists and is described correctly
Rainbow trout
A taxonomic claim naming both binomials, with the life-history contrast being the useful content.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: That Oncorhynchus mykiss and Oncorhynchus tshawytscha are congeners in the genus Oncorhynchus, the Pacific salmon and trout.States this directlyPassage read and verified
Sockeye salmon
A comparison resting on documented feeding morphology and naming both binomials.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: That Oncorhynchus nerka and Oncorhynchus tshawytscha are congeners in the genus Oncorhynchus with differing feeding ecology.States this directlyPassage read and verified
How it is caught
What these connections rest on (1)
Practitioner consensus — 1 connection
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Trolling
A practitioner claim about the principal marine method for the species.
- General angling website restatements of established technique — Various (Credible secondary source)Relied on for: Widely restated practitioner accounts of trolling and mooching for Pacific salmon in coastal waters.Citation checked — the work exists and is described correctly
- Sea Angler — Bauer Media (Specialist angling publication)Relied on for: Practitioner treatment of trolling technique for salmon and other pelagic species.Citation checked — the work exists and is described correctly
Gear for this fish
What these connections rest on (1)
Practitioner consensus — 1 connection
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Spoons
A practitioner claim about which lure family answers this species' feeding or holding behaviour.
- General angling website restatements of established technique — Various (Credible secondary source)Relied on for: Widely restated North American lure practice for this species.Background and mechanism onlyCitation checked — the work exists and is described correctly
- IGFA International Angling Rules and World Record Requirements — International Game Fish Association (Angling or fisheries organisation)Relied on for: Recognition of the species as an established sport fish taken on artificial lures, and the tackle conventions used for it.States this directlyPassage read and verified
Where it lives
What these connections rest on (1)
Scientific evidence — 1 connection
Supported by peer-reviewed research or fisheries science. The sources are listed and can be checked.
Spate rivers
A claim that the species uses rain-fed rivers on impermeable geology, resting on documented distribution and spawning habitat rather than on angling report.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: Recorded depth range, temperature tolerance and habitat association for the species outside north-west Europe.States this directlyPassage read and verified
- The IUCN Red List of Threatened Species — International Union for Conservation of Nature (Conservation authority)Relied on for: Global conservation assessment, range and recorded threats for the species.States this directlyCitation checked — the work exists and is described correctly
Reviewed 2026-08-10. FishingHQ does not state what any rule is or where any rule applies. Where this page says the two species are managed differently, that is a reason to check the authority for the water you are on — not a statement of what it requires.