Rainbow Darter

The rainbow darter is a small, benthic freshwater fish found in many creeks and small to medium-sized rivers throughout North America. In particular, it is common throughout the eastern United States, specifically throughout the Great Lakes and Ohio River Valley regions. Its distribution extends south to northern parts of Alabama and as far west as Missouri and Arkansas. This distribution has been suggested to be due to once existing glaciers and to its intolerance of brackish water. One study to examine the phylogeography of E. caeruleum and its colonization patterns found its distribution is greatly due to historic glaciations, and furthermore, due to distributions from drainages which have since then resulted in the current morphological diversity of the rainbow darter. Geographically, the rainbow darter is one of the most abundant and common darter species.

The rainbow darter is classified as insectivorous, feeding on small invertebrates such as insects and crayfish, but it has also been known to feed on some fly larvae. In Four-Mile Creek in Ohio, the rainbow darter lives primarily on trichopterans (i.e. caddisflies), having two feeding peaks: one in the morning and a second in the late afternoon or early evening.