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Lake Chub - Couesius plumbeus

Native/Non-native Species
(depends on location or taxa)

Global Rank: G5
State Rank: S5
(see State Rank Reason below)

Agency Status


External Links

State Rank Reason (see State Rank above)
Currently ranked a S5 because it is common, widespread, and abundant (although it may be rare in parts of its range). Not vulnerable in most of its range.
General Description
The lake chub is a native minnow found in Montana's eastern and northern drainages. They are an indicator species of the core prairie fish assemblage found in the Perennial Prairie Stream Aquatic Ecological System. Lake chubs are usually 6 inches or less in length (can be confused with creek chubs in the southern part of their MT range), and are reported to be an important forage fish in some locations. Lake chubs generally prefer small, slow streams and have been illegally introduced in several mountain lakes.

Diagnostic Characteristics
Silver gray overall, dusky on back, underside whitish. A midside band is present but often indistinct. Scattered dark scales may be present, giving a speckled appearance. Breeding males develop reddish patches, particularly on the pectoral fin bases. A well-developed, rounded barbel is located slightly above each corner of the mouth.

Species Range
Montana Range Range Descriptions

All Ranges
(Click legend blocks to view individual ranges)

Western Hemisphere Range


Observations in Montana Natural Heritage Program Database
Number of Observations: 1390

(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)

Runs out of lakes up to a mile or more to spawn in streams.

Favors creek type habitat, mostly at lower elevations, and is rarely found in the larger streams. Also in some mountain lakes.

Food Habits
Feeds on plankton and small aquatic invertebrates

May cross with longnose dace. No hybrids reported in Montana.

Reproductive Characteristics
Most are sexually mature at 3 yrs. Spawns mid May - mid June when water temps. reach 50 degrees F. No parental care. Eggs hatch in 10 days at 56 degrees F.

  • Literature Cited AboveLegend:   View Online Publication
    • Lee, D.S., C.R. Gilbert, C.H. Hocutt, R.E. Jenkins, D. E. McAllister, J. R. Stauffer, Jr. 1980. Atlas of North American freshwater fishes. North Carolina State Musuem of Natural History. 867 p.
    • Scott, W.B. and E.J. Crossman. 1973. Rainbow trout, Kamloops trout, Steelhead trout Salmo gairdneri Richardson. pp. 184-191. In: Freshwater fishes of Canada. Ottawa, Canada: Fisheries Research Board of Canada, Bulletin 184. 966 p.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Barndt, S.A. 1996. The Biology and Status of the Arctic Grayling in Sunnyslope Canal, Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 136 p.
    • Clancey, C.G. 1978. The fish and aquatic invertebrates in Sarpy Creek, Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 54 p.
    • Duncan, M.B. 2019. Distributions, abundances, and movements of small, nongame fishes in a large Great Plains river network. Ph.D. Dissertation. Bozeman, MT: Montana State University. 255 p.
    • Gilham, A.T. 2016. Relationship between intensity of livestock grazing and trout biomass in headwaters of east front rocky mountain streams, Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 45 p.
    • Hendricks, P., S. Lenard, D.M. Stagliano, and B.A. Maxell. 2013. Baseline nongame wildlife surveys on the Fort Peck Indian Reservation. Report to the Assiniboine and Sioux Tribes of the Fort Peck Indian Reservation. Montana Natural Heritage Program, Helena, MT. 83 p.
    • Joslin, Gayle, and Heidi B. Youmans. 1999. Effects of recreation on Rocky Mountain wildlife: a review for Montana. [Montana]: Montana Chapter of the Wildlife Society.
    • Mullen, J.A. 2007. Spatiotemporal variation of fish assemblages in Montana prairie streams. M.Sc. Thesis. Bozeman, MT: Montana State University. 102 p.
    • Mullins, M.S. 1991. Biology and predator use of cisco (Coregonus artedi) in Fort Peck Reservoir, Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 68 p.
    • Poole, A.S. 2019. Evaluation of embryo suppression methods for nonnative Lake Trout in Yellowstone Lake, Yellowstone National Park, Wyoming, USA. M.Sc. Thesis. Bozeman, MT: Montana State University. 108 p.
    • Reinhart, D.P. 1990. Grizzly bear habitat use on cutthroat trout spawning streams in tributaries of Yellowstone Lake. M.Sc. Thesis. Bozeman, MT: Montana State University. 128 p.
    • Sanborn, B.W. 1990. The ecology of Rainbow Trout in the Bighorn River, Montana. M.Sc. Thesis. Bozeman, Montana: Montana State University. 63 p.
    • Schultz, L.P. 1941. Fishes of Glacier National Park, Montana. USDI Conservation Bulletin No. 22. Washington D.C.: US Government Printing Office. 42 p.
    • Stash, S.W. 2001. Distribution, relative abundance, and habitat associations of Milk River fishes related to irrigation diversion dams. M.Sc. Thesis. Bozeman, MT: Montana State University. 82 p.
    • Stringer, A.L. 2018. Status of Northern Pearl Dace and chrosomid dace in prairie streams of Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 150 p.
    • Williams, J.R. 2019. Quantifying the spatial structure of invasive Lake Trout in Yellowstone Lake to improve suppression efficacy. M.Sc. Thesis. Bozeman, MT: University of Montana. 66 p.
    • Wuellner, M.R. 2007. Influence of reach and watershed characteristics on fish distributions in small streams of eastern Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 80 p.
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Citation for data on this website:
Lake Chub — Couesius plumbeus.  Montana Field Guide.  .  Retrieved on , from