Darters
Aiton's Encyclopedia (1910)
a group of small fishes, one to eight inches long, related to the perch. The smallest American species and one of the smallest of fishes, one to one and one-half inches in length, lives in the gravel bottoms of running streams from Minnesota to Indiana. Dr. S. A. Forbes writes: "Given a supply of certain kinds of food nearly inaccessible to the ordinary fish, it is to be expected that some fishes will become especially fitted for its utilization. These darters are the mountaineers among fishes. Forced from the populous and fertile valleys of the river beds and lake bottoms, they have taken refuge from their enemies in the rocky highlands, where the free waters play in ceaseless torrents, and there they have wrested from stubborn nature a meager living. Although diminished in size by their constant struggle with the elements, they have developed an activity and hardihood, a vigor of life and a glow of high color, almost unknown among the easier livers of the lower lands. Notwithstanding their trivial size, they do not seem to be dwarfed so much as concentrated fishes." Jordan adds, "Their colors are often very brilliant, the males of some species being among the most brilliant fishes known. The sexes are usually unlike; the females being generally dull and speckled. They usually prefer clear running water, where they lie on the bottom concealed under stones, darting, when frightened or hungry, with great velocity for a short distance, by a movement of the large pectorals, then stopping as suddenly. They rarely leave the bottom, and are never seen suspended in the water. A few species prefer a sandy bottom, where they lie buried in the sand, with only one eye visible. The darters feed chiefly on the larvae of flies. The largest reach a length of eight inches, but the average is about two and one-half inches." See Fish
What Has Changed in the Last Century
The natural history in Aiton's 1910 entry still holds: darters are bottom-hugging relatives of the perch, brilliantly coloured in the breeding males, and Forbes's description of them as "the mountaineers among fishes" is still quoted with affection. What has grown is the roll-call: where Jordan knew several dozen species, ichthyologists now recognise well over 200 in the subfamily Etheostomatinae, many of them named since the 1950s from single Appalachian and Ozark drainages, making darters one of the most species-rich groups of North American freshwater fishes. Their dependence on the "clear running water" Jordan noted has also made them casualties of dams and silt: the snail darter, discovered in the Little Tennessee in 1973, halted the Tellico Dam and reached the U.S. Supreme Court in the 1978 Endangered Species Act case TVA v. Hill.
Written for this edition, 2026.