In the absence of undercuts, the redbelly dace has the unusual habit of congregating in closely packed schools in midstream. Most other species of minnows would instead hide under objects. Streamside vegetation and its cooling effect on water temperature are essential components of their habitat. But more important, perhaps, is the need for a clean gravel substrate. Aggregations of spawning dace gather near shallow gravel riffles.
Males wait in swift water over the gravel for the gravid females to dart up from placid water below.
The females are attended by one male on each side. Many prickly protuberances called tubercles cover the skin of the males around the head and sides, as well as across the pectoral fins. With the texture of coarse sandpaper, these organs are used to hold the female in place as eggs are extruded for fertilization. The males vibrate vigorously from head to tail, and fertilized eggs drop into open spaces in the gravel, where they are protected from predators. Each spawning event is completed in a matter of seconds.