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Pygmy Whitefish

Pygmy Whitefish

The Pygmy Whitefish (Prosopium coulterii) is Idaho's smallest native whitefish species and one of North America's most primitive coregonines.

These glacial relicts serve as important forage fish for larger predatory species including trout, burbot, and northern pike.

Scientific Name: Prosopium coulterii

Physical Characteristics:

Measuring typically 4-6 inches with some reaching up to 12 inches. These glacial relicts have a cigar-shaped, cylindrical body with brownish-green backs, silvery sides, and white bellies.

Distinguished by their large eyes (diameter larger than snout length), small toothless mouths, single nostril flaps, and 54-79 lateral line scales.

What to know

Habitat Distribution

Found throughout portions of the Columbia River system in Idaho. In Idaho, Pygmy Whitefish inhabit cold, deep lakes and their tributary streams

Key Locations

Focus on deep, cold lakes and their tributary streams throughout Idaho's Columbia River drainage system

Specific Spots

Focus on deeper pools, lake drop-offs, and areas near tributary stream mouths. They typically occupy depths greater than 30 meters in lakes but can be found from less than 5 meters to as deep as 168 meters.

Pygmy Whitefish FAQ

Answers from onWater's species guide.

What flies work for Pygmy Whitefish in Idaho?

Use small nymph patterns in sizes 14-22, with the Prince Nymph being particularly effective - this pattern acts like 'whitefish candy' and consistently outperforms other flies. Beadhead nymphs work best as they help get down to the fish's preferred bottom-hugging habitat.

When is the best time to fish for Pygmy Whitefish in Idaho?

Target from May through November when they're most active and accessible to anglers, avoiding the late fall/winter spawning period (September-January)

How do you catch Pygmy Whitefish in Idaho?

Fish these patterns under strike indicators or use tight-line nymphing techniques to maintain contact with the bottom where Pygmy Whitefish feed. Since they inhabit deep water (often 30+ meters), use weighted flies or add split shot to reach proper depths.

What do Pygmy Whitefish eat?

These fish are generalist carnivores feeding primarily on benthic invertebrates including crustaceans, chironomid larvae and pupae, caddisfly larvae, mayfly nymphs, stonefly nymphs, small mollusks, and fish eggs.

Where do Pygmy Whitefish live in Idaho?

Found throughout portions of the Columbia River system in Idaho. In Idaho, Pygmy Whitefish inhabit cold, deep lakes and their tributary streams

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