Mountain Sucker - Catostomus platyrhynchus
FWP Conservation Tier
The mountain sucker has a more limited habitat than other Montana suckers. It is virtually limited to running waters east of the Divide. It also is the smallest sucker in Montana with its largest specimens having a length of about 9 inches.
Back and upper sides are dusky or dark green with black specks; may have dark mottling shaped like saddles across the back; lower body whitish. Both sexes have a reddish orange band along sides during breeding season; band is brighter, longer, and wider in male. Mouth is so long it sometimes exceeds head width. See Snyder and Muth (1990) for a guide to the identification of larvae and early juveniles. No other Montana sucker has a notch in each corner of mouth.
Western Hemisphere Range
Summary of Observations Submitted for Montana
Number of Observations:
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Map Help and Descriptions
(Records associated with a range of dates are excluded from time charts)
Cold, clear streams with rubble, gravel or sand bottoms; sometimes turbid streams but seldom lakes. Found principally in riffle habitat in middle Missouri River study.
Mostly algae, aquatic plants and invertebrates obtain from the cobbles and pebbles from the stream bottom.
Young prefer slower side channels or weedy backwaters. Seldom exceed 6 inches in length as adults.
Sexually mature : males in 2 -3 yrs., females in 4 years. Spawns June - July when water temperatures exceed 50 degrees F. Incubation period probably short.