[10] The type specimen was collected by Acting Assistant Surgeon, George Scott Oximixon, U.S. Army near Camp Baker, Montana Territory.

Milner also based his description on three specimens taken by geologist Ferdinand V. Hayden during his Geological Survey of 1872 from Willow Creek in Gallatin County, Montana.

A band of gold forms a border between their sides and white bellies, which are in sharp contrast to their pelvic fins striated with iridescent orange, red, or pink.

The historic native range of the fluvial form of Montana Arctic grayling encompasses the mainstem and tributaries of the upper Missouri river as far downstream as the Great Falls.

[14] During the 1804–1806 Lewis and Clark Expedition, the explorers did not encounter the Montana grayling until they reached the Beaverhead river, a secondary tributary of the Missouri.

[14] In 1915, U.S. Bureau of Fisheries biologist, W.C. Kendall described the Montana grayling as "abundant" in the Madison, Firehole and Gibbon rivers in Yellowstone National Park.

The introduction of non-native brook, brown and rainbow trout into the upper Missouri river basin which began in the 1890s initiated a severe decline in fluvial grayling populations and range.

In Howard Back's 1938 work The Waters of Yellowstone with Rod and Fly, he lamented that he was unable to find any grayling in the Madison river.

Fish Commission personnel stocked Grebe Lake, at that time fishless, with a lacustrine form of the Montana arctic grayling.

Juvenile grayling are weak swimmers and prefer rearing habitat along stream margins that serve as velocity refuges, back-waters in side channels, or waters adjacent to beaver dams.

Adfluvial forms of Montana grayling feed and overwinter in lake environments and migrate up suitable tributary streams to spawn.

The goal of the agreement was to secure and enhance a population of fluvial Arctic grayling (Thymallus arcticus) within the upper reaches of their historic range in the Big Hole River drainage.

This marks a landmark decision and success story sparked in the early 1990s with the Arctic Grayling Recovery Program and Big Hole Watershed Committee and precipitated by the expansive Conservation Candidate Agreement with Assurances (CCAA).

Three fluvial brood stock populations are located at the Yellowstone River Trout Hatchery, Axolotl Chain of Lakes, and Green Hollow II Reservoir.

[11] An environmental DNA assay using 5 liters (1.3 U.S. gal) of streamwater has been developed to identify grayling with high specificity against other native and non-native salmonids in Montana.