The Blacknose Dace is brownish to black above, and the sides are speckled with dark scales giving the fish a mottled appearance. A dusky lateral band is outlined above by a row of light scales. Spawning males develop a pick to red-colored lateral band. The sub-terminal mouth is oblique with equal jaws, and a barbell is present on the posterior tip of the mandible. The upper lip is attached to the snout without a groove (a feature know as a frenulum), which is characteristic of Rhinicthys. There are from 62 to 71 scales in the complete lateral line. Hooked pharyngeal teeth are arranged in a formula of 2, 4-4, 2. The peritoneum is silvery colored, and the air bladder is fairly well developed. Dorsal and pelvic fins contain 8 rays, while the anal fin has 7, and the pectoral fins from 13 to 16 rays.
The Blacknose Dace is found throughout central and northeast Iowa, where they are common with scattered populations found in Osceola, Dickinson and Emmet counties. They are absent from the southeastern part of the state and the Missouri River drainage. The Iowa distribution of this minnow seems to be increasing, and they appear to be flourishing in the trout streams.
Aquatic insects and larvae.
Grows up to 4 inches. State Records are not documented for non-game species.
Blacknose Dace are sometimes called the "riffle daces" because they prefer clear waters with swift currents over a rocky substrate, which explains their thriving in Iowa's trout streams.
The Blacknose Dace is common throughout central and northeast Iowa, with scattered populations also being found in the Little Sioux River, Big Sioux River, Rock River and Floyd River drainages. However, it appears to be absent from southeast Iowa. The distribution of the Blacknose Dace in Iowa seems to be increasing, especially in the river networks in northeast Iowa (Eastern Broadleaf Forest Aquatic Subregion).
Spawning takes place from May through July, when males build a nest of gravel and guard a well-defined territory. Eggs are 1/6 to 1/8 inch in diameter. Young Blacknose Dace range from 1 1/2 to 2 inches in length by the end of the first season. Adults reach up to 4 inches in length. Food consists largely of aquatic insects and larvae.
The Blacknose Dace was first listed as the Western Blacknose Dace (Rhinichthys Atratulas Meleagris), which is probably the correct interpretation for this minnow in Iowa.
The Blacknose Dace seems to prefer clear, cool headwater and medium-sized streams over gravel bottoms. It is common in moderate to rapidly flowing water and appear to reach its greatest abundance in trout streams such as in northeast Iowa.
The Blacknose Dace has a growing population and is viewed as secure according to the Iowa Wildlife Action Plan.
Recent stream sampling information is available from Iowa DNR's biological monitoring and assessment program.
Harlan, J.R., E.B. Speaker, and J. Mayhew. 1987. Iowa fish and fishing. Iowa Conservation Commission, Des Moines, Iowa. 323pp.
Iowa Department of Natural Resources, Iowa Wildlife Action Plan
Loan-Wilsey, A. K., C. L. Pierce, K. L. Kane, P. D. Brown and R. L. McNeely. 2005. The Iowa Aquatic Gap Analysis Project Final Report. Iowa Cooperative Fish and Wildlife Research Unit, Iowa State University, Ames
Illustration by Maynard Reece, from Iowa Fish and Fishing