Redside Dace

Featured Species at Risk - Redside Dace: Endangered

Ontario Redside Dace Distribution. Modified from Mandrak and Crossman 1992; Parker et al. 1988.
Ontario Redside Dace Distribution. Modified from Mandrak and Crossman 1992; Parker et al. 1988.

Redside Dace (Clinostomus elongatus) is the only minnow species to hunt flying insects by leaping out of the water. These bright and colorful minnows are predominately silver and have a large red/orange streak running along their sides; when they capture their food, they appear as shots of glimmer over the water. For their small size (7.5 to 12 centimetres [3 to 5 inches]), Redside Dace have relatively large mouths and sets of eyes, which help them to search for prey and capture flying insects.

Where Do They Live?

Redside Dace habitat.
Redside Dace habitat.

In Canada, this species is found in streams that flow into Lakes Ontario, Huron, and Erie, predominantly in tributaries of western Lake Ontario. Redside Dace have been found in streams in Conservation Halton’s watershed, including Sixteen Mile Creek, Fourteen Mile Creek, and Bronte Creek. Redside Dace, like most species, have specific habitat needs:

  • The ideal habitat for Redside Dace are streams with clean, cool, clear water flowing over gravel and rubble bottoms;
  • Redside Dace need a mixture of both pools and shallow, rippled waters;
  • They spend most of their time in mixed-species schools at mid-depth positions of streams;
  • Redside Dace prefer areas with healthy and abundant stream-side vegetation; they rely on overhanging foliage and submerged branches, as well as undercut banks, for cover and food sources; 
  • Redside Dace spawn in the spring, in riffles and shallow flowing pools in or near the nests of Common Shiner and/or Creek Chub; the guarding behaviour of these other fish species helps protect Redside Dace eggs, thereby contributing to their survival.

Why Are They Considered “Endangered”?

Redside Dace were once found in 24 watersheds in Ontario. In 1987 the species was considered provincially vulnerable, and by 2000, it was designated threatened. It is now found in 16 watersheds. In 2009, due to population decline and a reduction in the length of streams they live in, the status of Redside Dace was elevated to endangered under Ontario’s Endangered Species Act, 2007.

The species’ decline is most likely a result of impacts from urban development, particularly impacts associated with uncontrolled or inadequately controlled stormwater flowing into streams. Increasing threats include, but are not limited to: clearing of streamside vegetation; erosion and subsequent siltation (where small particles of sand and clay remain suspended in the water column or settle on the bottom covering other types of important substrate/habitat); and other changes in water quantity and quality. Agricultural activities such as pesticide use can decrease the minnow’s food sources. Redside Dace populations can also be impacted by the introduction of non-native fish that prey on Redside Dace and compete for the same resources that are important for Redside Dace survival.

What Is Being Done?

Monitoring efforts.
Monitoring efforts.

Conservation Halton ecologists actively monitor changes over time in Redside Dace populations and habitat conditions. Conservation Halton also focuses on habitat protection and rehabilitation, and in raising awareness of the needs and plight of this species.  The long-term recovery goal is to restore viable populations to their full southern Ontario range and remove this species from the endangered species’ list.

More Information

Cited Resources

Mandrak, N.E. and E.J. Crossman. 1992. A checklist of Ontario freshwater fishes. Royal Ontario Museum, Toronto. 176 pp.

Parker, B.J., P. McKee and R.R. Campbell. 1988. Status of Redside Dace, Clinostomus elongatus, in Canada. Canadian Field-Naturalist 102: 163-169.