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Montana Field Guides

Columbia Slimy Sculpin - Cottus cognatus

Native Species

Global Rank: G5
State Rank: S5

Agency Status


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General Description
The slimy sculpin is native west of the Continental Divide, and a recent study (Neely 2010) showed through DNA work that the Columbia Basin slimy sculpin is more closely related to a Russian sculpin in Siberia--not the slimy sculpin of the eastern U.S., as some previously thought. Like the rocky mountian sculpin, it prefers clear, cold, rocky streams but will also be found along cobbly shorelines of lakes. Like all sculpins, this species is a benthic invertivore meaning it eats primarily aquatic insects. They occasionally eat small fish or trout eggs but this is not a large part of their diet. All freshwater sculpins are spring spawners. The males select spawning sites on the undersides of rocks. The female is courted, enters the nest, and deposits a mass of adhesive eggs upside down on the ceiling of the nest. The male then guards the nest and newly-hatched young sculpins with vigilance.

Diagnostic Characteristics
The back and sides are brown to black with mottling; dark bands are often present. The underside is white. The first dorsal fin is fringed with orange on breeding males. No palatine teeth are present. Pelvic fins have 3 or 4 soft rays; if a fourth (inner) ray is present, it is usually two-thirds or less the length of the longest. Other Montana sculpins have four fully developed soft rays. Note: sculpin pelvic fins have one spine in addition to the soft rays. It is encased in a fleshy membrane with the first (outer) ray and is not distinct.

Species Range
Montana Range


Western Hemisphere Range


Range Comments
Found throughout western MT in cold, clear rivers and streams.

Observations in Montana Natural Heritage Program Database
Number of Observations: 656

(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)

Its usual habitat is in the rocky riffles of cold, clear streams, but it is sometimes found along the rubble beaches of lakes, especially near the mouths of inlet streams (Brown 1971).

Food Habits
Food is comprised of mostly immature aquatic insects and invertebrates, but also includes any small fish available (Brown 1971).

Construction of the Libby Dam wiped out populations in a stretch of river now occupied by Lake Koocanusa (Huston 1984).

Reproductive Characteristics
Spawning occurs in spring (Brown 1971). Incubation is in 30-40 days at 48-50 degrees F. They may become sexually mature at 2 years (Weisel 1957). Populations in northern Saskatchewan spawned in early May at 46 degrees F. with eggs hatching in 4 weeks (Scott 1973).

  • Literature Cited AboveLegend:   View Online Publication
    • Brown, C.J.D. 1971. Fishes of Montana. Montana State University, Bozeman, MT. 207 pp.
    • Huston J.E., P. Hamlin; B. May 1937-; Montana. Dept. of Fish, Wildlife, and Parks.; United States. Army. Corps of Engineers. Seattle District. 1984
    • Neely, D.A. 2010. Systematics of Montana sculpins, final report on activities conducted during 2009–2010. Tennessee Aquarium Conservation Institute, Cohutta, Georgia.
    • Scott, W.B. and E.J. Crossman. 1973. Freshwater fishes of Canada. Fisheries Research Board of Canada, Bulletin 184. 966 pp.
    • Weisel, G.F. 1957. Fish guide for intermountain Montana. Montana State University Press. Missoula, MT. 88 pp.
  • Additional ReferencesLegend:   View Online Publication
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    • Bahn, L. 2007. An assessment of losses of native fish to irrigation diversions on selected tributaries of the Bitterroot River, Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 118 p.
    • Brandt, S. B. 1986. Ontogenetic shifts in habitat, diet and diel-feeding periodicity of slimy sculpin in Lake Ontario. Trans. Am. Fish. Soc. 115:711-715.
    • Brandt, S., and S. Madon. 1986. Rainbow smelt, Osmerus mordax, predation on slimy sculpin, Cottus cognatus, in Lake Ontario. J. Great Lakes Res. 12:322-325.
    • Burford, D.D. 2005. An assessment of culverts of fish passage barriers in a Montana drainage using a multi-tiered approach. M.Sc. Thesis. Bozeman, MT: Montana State University. 50 p.
    • Cuker, B. E., M. E. McDonald, and S. C. Mozley. 1992. Influences of slimy sculpin (Cottus cognatus) predation on the rocky littoral invertebrate community in an arctic lake. Hydrobiologia 240:83-90.
    • Edson, S.A. 1992. Sculpin (Cottus) distribution in the Kootenai National Forest and northwestern portions of the Flathead National Forest, Montana. Montana Natural Heritage Program, Helena. 37 pp. including appendices.
    • Gangemi, J.T. 1992. Sculpin (Cottus) distribution in the Kootenai National Forest and western portions of the Lolo National Forest, Montana. Montana Natural Heritage Program, Helena, MT 59620. 54 pp.
    • Godkin, C. M., W. J. Christie, and D. E. McAllister. 1982. Problems of species identity in the Lake Ontario sculpins Cottus bairdi and C. cognatus. Can. J. Fish. Aquat. Sci. 39:1373-1382.
    • Hanson, K. L., A. E. Hershey, and M. E. McDonald. 1992. A comparison of slimy sculpin (Cottus cognatus) populations in arctic lakes with and without piscivorous predators. Hydrobiologia 240:189-201.
    • Hughes, G.W. and A.E. Peden. 1984. Life history and status of the shorthead sculpin (Cottus confusus: Pisces, Cottidae) in Canada and the sympatric relationship to the slimy sculpin (Cottus cognatus). Canadian Journal of Zoology 62:306-311.
    • Lawler, G. H. 1952. A new North American host for the fish parasite Triaenophorus nodulosus (Pallus). Can. Field-Nat. 66:111. [in C. cognatus]
    • Lemoine, M., M.K. Young, K.S. McKelvey, L. Eby, K.L. Pilgrim and M.K. Schwartz. 2014. Cottus schitsuumsh, a new species of sculpin (Scorpaeniformes: Cottidae) in the Columbia River basin, Idaho-Montana, USA. Zootaxa 3755(3):241-258.
    • Lyons, J. 1990. Distribution and morphological variation of the slimy sculpin (Cottus cognatus) in the north central United States. Canadian Journal of Zoology 68:1037-1045.
    • McAllister, D. E. 1964. Distinguishing characters for the sculpins Cottus bairdii [sic] and C. cognatus in eastern Canada. J. Fish. Res. Board Can. 21:1339-1342.
    • Mousseau, T. A., N. C. Collins, and G. Cabana. 1988. A comparative study of sexual selection and reproductive investment in the slimy sculpin, Cottus cognatus. Oikos 51:156-162.
    • Otto, R., and J. Rice. 1977. Responses of a freshwater sculpin (Cottus cognatus gracilis) to temperature. Trans. Am. Fish. Soc. 106:89-94.
    • Owens, R.W., and R.A. Bergstedt. 1994. Response of slimy sculpins to predation by juvenile lake trout in southern Lake Ontario. Transactions - American Fisheries Society. 123(1): 28-36.
    • Petrosky, C., and T. Waters. 1975. Annual production by the slimy sculpin population in a small Minnesota trout stream. Trans. Am. Fish. Soc. 104:237-244.
    • Savino, J. F., and M. G. Henry. 1991. Feeding rate of slimy sculpin and burbot on young lake char in laboratory reefs. Environ. Biol. Fishes 31:275-282.
    • Strauss, R. E. 1986. Natural hybrids of the freshwater sculpins Cottus bairdi and Cottus cognatus (Pisces: Cottidae): electrophoretic and morphometric evidence. Am. Mid. Nat. 115:87-105.
    • Symons, P., J. Metcalfe, and G. Harding. 1976. Upper lethal and preferred temperatures of the slimy sculpin, Cottus cognatus. J. Fish. Res. Board Can. 33:180-183.
    • Zimmerman, E.G., and M.C. Wooten. 1981. Allozymic variation and natural hybridization in sculpins, Cottus confuses and Cottus cognatus. Biochemical Systematics and Ecology 9(4):341-346.
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Citation for data on this website:
Columbia Slimy Sculpin — Cottus cognatus.  Montana Field Guide.  .  Retrieved on , from