Greenthroat Darter (Etheostoma lepidum) is a small (6 cm) fish that can be found in tributaries of the Colorado, Guadalupe, and Nueces rivers in Texas and the Pecos River system in southeastern New Mexico, but have been extirpated from the Pecos River below Carlsbad and from the Black River. They inhabit vegetated riffles in swift-flowing streams and sinkholes or shore areas that experience wave action.