All about Rainbow Darters
What's In a name?
Rainbow darter -- named from the range of colors displayed by males during the spawning season.
Etheostoma (ee-thee-ah´-stoe-mah) taken from the word etheo meaning to filter, and stoma meaning mouth in Greek caeruleum (sair-rule´-ee-um) means blue in Latin.
Where Do They Live?
Perhaps Minnesota's most colorful fish they are common in rivers like the Cannon, Zumbro, Root, and Cedar in the southeastern part of the state. They are much less common in the lower St. Croix River and in the tributaries of the Minnesota River. They have also been found in the Red River drainage, but only in the Otter Tail River. Rainbow darters prefer clear water in areas of moderate to fast current with a rocky stream bottom, habitat usually associated with riffles. Their presence is often an indication of a high-quality resource because they do not tolerate most forms of water pollution or habitat alteration.
How Big Do They Get?
Rainbow darters are tiny relatives of the walleye. They typically grow 2 to 3 inches in length and rarely live beyond the age of three.
What Do They Eat?
Young rainbow darters eat mostly small crustaceans. As they grow into adulthood the size of their food gets larger and they eat a greater variety of items including insect larvae, young crayfish, snails, and the eggs of other small fishes.
What Eats Them?
Rainbow darters have only rarely been found in the stomachs of other fishes; however, they are undoubtedly eaten by predatory fishes such as the burbot, large stonecats, and smallmouth bass. Fish-eating birds such as the great blue heron are also likely predators. Humans do not eat them, and they are illegal to use as bait.
Lake Phalen in Ramsey County is the only lake in the world where rainbow darters have been found.
Credits: Photograph by Konrad P. Schmidt. Text modified from Bell Museum of Natural History, Fishes of Minnesota Web site (Nicole Paulson & Jay T. Hatch authors)