Arctic Grayling
A cold-water salmonid best known for its oversized, sail-like dorsal fin. Montana's fluvial Arctic grayling population is one of the last native river populations in the lower 48 states.
- Scientific name
- Thymallus arcticus
- Family
- Salmonidae
- Adult size
- Typically 10–16 inches; larger in lake populations.
Identification
Slender, silvery-lavender body with a tall, iridescent dorsal fin flecked with rows of pink and turquoise spots — unmistakable among North American freshwater fish.
Habitat
Cold, clear rivers, streams, and high-elevation lakes with strong current and gravel bottoms.
Diet
Aquatic and terrestrial insects taken at or near the surface.
Angling
A popular dry-fly target in Montana and Utah's high-country waters, prized for its willingness to rise.
Conservation
Montana's native river (fluvial) grayling are a state species of concern; most fisheries today are lake populations sustained by stocking.
Where Arctic Grayling is stocked
When Arctic Grayling is stocked
Top Arctic Grayling waters
Yellowstone River
16 species · 1781 records
Last stocked October 2010
Missouri River
19 species · 1417 records
Last stocked October 2010
Boulder River
5 species · 1385 records
Last stocked July 1983
Madison River
5 species · 1310 records
Last stocked April 2006
Big Spring Creek
5 species · 1201 records
Last stocked July 1981
Flathead Lake
14 species · 1161 records
Last stocked October 1997
Georgetown Lake
5 species · 968 records
Last stocked June 2026
Hebgen Lake
4 species · 944 records
Last stocked June 2023
Trial Lake
SUMMIT County · 5 species · 900 records
Last stocked July 2026
Big Hole River
5 species · 893 records
Last stocked August 1993
Mirror Lake
DUCHESNE County · 4 species · 890 records
Last stocked July 2026
Pass Lake
DUCHESNE County · 4 species · 759 records
Last stocked July 2026
Rockport Reservoir
SUMMIT County · 5 species · 751 records
Last stocked May 2026
Butterfly Lake
DUCHESNE County · 4 species · 745 records
Last stocked July 2026
Beaver Creek
13 species · 697 records
Last stocked June 2014
Lake Mary Ronan
8 species · 685 records
Last stocked June 2026
Warm Spring Creek
6 species · 662 records
Last stocked July 2013
Teapot Lake
SUMMIT County · 5 species · 613 records
Last stocked July 2026
Moosehorn Lake
DUCHESNE County · 3 species · 599 records
Last stocked July 2026
Rock Creek
6 species · 595 records
Last stocked May 2013
Lilly Lake
SUMMIT County · 4 species · 515 records
Last stocked July 2026
Harpers Lake
5 species · 505 records
Last stocked June 2026
Gallatin River
3 species · 495 records
Last stocked April 2006
Silver Lake
UTAH County · 4 species · 467 records
Last stocked July 2026
Frequently asked
Where is Arctic Grayling stocked?
Arctic Grayling is stocked in 333 waters across 2 states: Montana, Utah.
When is Arctic Grayling stocked?
Arctic Grayling is typically stocked in summer, most often in June, based on records across every state that stocks it.
How many Arctic Grayling are stocked?
About 142,596,137,014,580,600,000 Arctic Grayling have been stocked on record since 1926, across Montana, Utah.
What size Arctic Grayling are stocked?
Stocked Arctic Grayling average about 3.9 inches, based on sizes reported by Montana, Utah.
What does a Arctic Grayling look like?
Slender, silvery-lavender body with a tall, iridescent dorsal fin flecked with rows of pink and turquoise spots — unmistakable among North American freshwater fish.