The wounfin (Plagopterus argentissimus) is a species of minnow endemic to the Virgin River of the southwestern United States. It is a slender, silvery minnow, with a flattened head and belly, long snout, leathery skin, and no scales. There are barbels on the corners of its lips, and its common name likely comes from the first spinous ray of its dorsal fin, which is sharp-pointed. Its maximum length is rarely more than 7.5 cm (3 in).