Rainbow Darter - Ecology

Ecology

Some important ecological characteristics of the rainbow darter are its diet, predators, and microhabitat preferences. It is classified as insectivorous, feeding on small invertebrates such as insects and crayfish, but it has also been known to feed on some fish larvae. In Four-Mile Creek in Ohio, the rainbow darter survived primarily on trichopterans (i.e. caddisflies), having two feeding peaks: one in the morning and a second in the late afternoon or early evening. Following the food web, the primary predators of the rainbow darter are larger freshwater fish, such as burbots (Lota lota), stonecats (Notorus flavus), and smallmouth bass (Micropterus dolomieu).Like many other darter species, it has the ability to maintain position on the substrate in flowing water. This unique characteristic plays a key role in its microhabitat preference. E. caeruleum has been shown to prefer creeks and rivers with rocky substrates and swift-moving riffles. This microhabitat preference has been suggested to be due to oxygen levels in the water during season changes or other factors, such as feeding or shelter-related habitat preferences. Because E. caeruleum has such a low tolerance for brackish water, human-induced changes such as pollution or sewer drainage could cause a huge negative impact on its abundance.