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Montana Field Guide

Montana Field Guides

Brook Trout - Salvelinus fontinalis

Non-native Species

Global Rank: G5
State Rank: SNA

Agency Status


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General Description
The "brookie" or brook trout was introduced to Montana from eastern North America in 1889. It too, was extensively propagated and stocked in the early half of this century, although seldom so today. Brook trout favor small, cold, headwaters streams and ponds, particularly those that are spring-fed. Brook trout are common throughout most of the western two-thirds of the state in all major drainages. Many an angler learned to fish for brookies as a kid. Spawning occurs in typical trout-like fashion with eggs deposited in a gravel redd during the fall. Brook trout are frequently able to spawn successfully in ponds which have upwelling springs. Brook trout will eat nearly any living organism, and larger fish can be voracious predators on other fish and even their own young. Brook trout are a handsome game fish in their own right, but indiscriminate stocking in mountain lakes has resulted in irreversibly stunted populations in many cases. Trophy brook trout up to 9 pounds have been taken in Montana waters.

Diagnostic Characteristics
Key diagnostic features include: wavy lines on back; dorsal fin with black markings; lateral red spots with blue halos; tail fin squarish or slightly forked; pectoral, pelvic, and anal fins with white leading edge set off by black line (Holton and Johnson 1996).

Species Range
Montana Range


Observations in Montana Natural Heritage Program Database
Number of Observations: 12587

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Prefers small spring fed streams and ponds with sand or gravel bottom and vegetation. Clear, cool water (Brown 1971, Holton 1981). Spawns over gravel in either streams or lakes with percolation;spring areas in lakes. Often overpopulates, resulting in fish too small to attract anglers.

Food Habits
Feed mainly on aquatic insects and other small aquatic invertebrates throughout life. Larger individuals may eat small fish (Brown 1971). Flathead River study found ephemeroptera and trichoptera were dominant insects in diet.

Stunting is often a problem in high mountain lakes and rapid cold mountain streams. May cross with brown trout to produce infertile tiger trout.

Reproductive Characteristics
Sexually mature usually in 2 years but may spawn after 1 year. Spawns Sept. - Oct. Eggs laid in redd and fry emerge Feb-April. Fry seek shelter in vegetation or shallow water near shore (Brown 1971).

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Citation for data on this website:
Brook Trout — Salvelinus fontinalis.  Montana Field Guide.  .  Retrieved on , from