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Longnose Dace - Rhinichthys cataractae

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Global Rank: G5
State Rank: S5

Agency Status
FWP Conservation Tier: 3


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General Description
The longnose dace has the most widespread distribution of all fish in Montana. It is found throughout all three of our major drainages. It is very adaptable, inhabiting almost every conceivable habitat: muddy and warm, clear and cold, streams and lakes. The largest longnose dace are about 6 inches long. They are well-adapted for living on the bottom of fast-flowing streams among the stones. Longnose dace eat mostly immature aquatic insects. They are probably one of the most important forage minnows for Montana's larger predatory game fish.

Diagnostic Characteristics
Back olive to black, shading to white or yellow underneath. Sides may have dark blotches. Breeding males have reddish orange on head and fins. Juveniles have a black midside stripe starting at the tip of the snout and ending at the base of the tail fin. Adults often have a dark stripe ahead of eye. Small barbel at each corner of mouth.

Species Range
Montana Range

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Western Hemisphere Range


Summary of Observations Submitted for Montana
Number of Observations: 2614

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Relative Density



(Records associated with a range of dates are excluded from time charts)

Habitat variable. Found in lakes, streams, springs (Brown 1971). Preferred habitat is riffles with a rocky substrate (Morris et al. 1981, Elser et al. 1980).

Food Habits
Eats mostly immature aquatic insects picked off the rocks. Small amounts of algae and a few fish eggs are also eaten (Brown 1971).

Showed a preference for main channel border habitat type in middle Missouri River study (Gardner and Berg 1980). Have declined after formation of Lake Koocanusa on the Kootenai River (Huston et al. 1983, Huston et al. 1984).

Reproductive Characteristics
Sexually mature probably in 3 yrs. Spawns late spring or early summer at 53 degrees F. in shallow riffle areas over gravel beds (Brown 1971). Middle Missouri River populations spawn early June to latter part of July. Peak in late June (Berg 1981).

  • Additional ReferencesLegend:   View WorldCat Record   View Online Publication
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    • Urban, Larry, 2002, Biological Resources Report: Wagner Pit Wetland Restoration Site. Proj. No. STPX 56(50) CN 4645. February 23, 2002. In Wgner Pit WS#13 Upper Yellowstone, Yellowstone County. Fin. Dist. 5 AdminDist 5.
    • Werdon, S.J. 1992. Population status and characteristics of Macrhybopsis gelida, Platygobio gracilis and Rhinichthys cataractae in the Missouri River Basin. South Dakota State University, Brookings, SD. M.S. Thesis, 55pp.
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Citation for data on this website:
Longnose Dace — Rhinichthys cataractae.  Montana Field Guide.  Montana Natural Heritage Program and Montana Fish, Wildlife and Parks.  Retrieved on April 1, 2015, from
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