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Arctic Grayling

Arctic Grayling

Arctic Grayling in Idaho are introduced fish that were historically stocked throughout the state's river systems.

These beautiful salmonids are primarily lacustrine (lake-dwelling) populations established in high-elevation alpine lakes in central Idaho's Boulder Mountains, where they thrive in cold, clear waters with high oxygen levels.

Scientific Name: Thymallus arcticus

Physical Characteristics:
  • Distinguished by their large, sail-like dorsal fin adorned with iridescent red, blue, or purple spots and colorful body markings ranging from silver to gold.
  • They can live up to 18-30 years, typically measure 10-24 inches, weigh 3-8 pounds.

What to know

Habitat Distribution

  • Historically stocked throughout the state's river systems.
  • Primarily lacustrine (lake-dwelling) populations established in high-elevation alpine lakes in central Idaho's Boulder Mountains.

Key Locations

  • Kootenai, Spokane, Salmon, Bear, and Snake river drainages.
  • Boulder Mountains alpine lakes and high-elevation waters in central Idaho where stocking has been most successful.

Specific Spots

  • Fish tributary inflows, shallow areas with rocky bottoms, deep pools below riffles, eddies created by structure, and anywhere shallow water drops into deep holes.
  • Target areas where current breaks around logs, boulders, or fallen trees.

Arctic Grayling FAQ

Answers from onWater's species guide.

What flies work for Arctic Grayling in Idaho?

Dr.y flies like tan elk hair caddis, bloody mosquito, mayflies, black gnats, bumblebee, and Royal Coachman patterns in sizes 8-14. Wet flies including hare's ear, Zug bug, Bitch Creek nymphs, and minnow streamers.

When is the best time to fish for Arctic Grayling in Idaho?

June through September when they're actively feeding. Early summer (June) and late summer through fall (August-September) provide peak fishing. Spring (May-June) spawning period should be avoided for fishing to protect spawning populations.

How do you catch Arctic Grayling in Idaho?

For spinning gear, cast with steady retrieves. Fly fishing is exceptionally productive. Present flies naturally with minimal drag. Look for feeding aggregations during insect hatches - when you find one grayling, expect multiple fish in the area.

What do Arctic Grayling eat?

They feed voraciously during summer months on drifting aquatic insects including blackflies, mayflies, stoneflies, and caddisflies, plus zooplankton, crustaceans, fish e.g.gs, and occasionally small fish or terrestrial insects.

Where do Arctic Grayling live in Idaho?

Historically stocked throughout the state's river systems. Primarily lacustrine (lake-dwelling) populations established in high-elevation alpine lakes in central Idaho's Boulder Mountains.

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