The greenthroat darter (Etheostoma lepidum) is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is found in Colorado, Guadalupe and Nueces River drainages in Texas; and in Pecos River system in New Mexico. Maximum size: 64 mm SL Coloration: Throat blue or green in males. 10 to 12 body bars. No black spot on upper margin of pectoral fins, no pale longitudinal streak along lateral line, and no large black rectangular blotches present on sides. Dorsum is olive; belly of male is orange, female yellow to white. 8-13 dark green-brown vertical bars along the side; bars encircle the body posteriorly, anteriorly extending ventrally only onto upper part of the belly. Interspaces between bars yellow and speckled with orange. Breast and branchiostegal membranes of male are green, those of female white. 3 vertically aligned spots at base of the caudal fin. Prominent black pre- and suborbital bars; postorbital bar reduced to a spot. In the male 1st dorsal fin has a blue-green margin, clear submarginal band, broad red-orange band, and in some areas of the species range a basal blue-green band. The 2nd dorsal and caudal fins have many red-brown spots arranged in concentric bands. Pelvic and anal fins mostly blue-green, often have orange or red-orange medially. Fins of the female mostly spotted with brown. Pelvic fins of both sexes clear. In breeding male, colors of fins are accentuated, breast and branchiostegal membranes bright blue-green, and bright orange blotches contrast with the dark green bars on the side of the body.
