Rio Grande Silvery Minnow

It is a stout, silvery minnow with moderately small eyes and a small mouth. Adults may reach 3.5 in (89 mm) in total length.

Rio Grande silvery minnows are herbivores whose diet is believed to consist of river plants and benthic macroinvertebrates, though little research has been conducted into their diet due to the difficulty of getting into their stomachs. They play a role in keeping water clean by eating algae. Silvery minnows tend to skim the bottom of rivers and streams and are prolific spawners. They serve as food source for other animals.

The Rio Grande silvery minnow was first listed on July 20, 1994. It is currently designated as endangered in its entire range. The population decline of the Rio Grande silvery minnow has been almost directly proportional to recent alterations to the Rio Grande over the past century. Multiple diversions for municipal and agricultural uses have occurred, including alteration of the natural hydrograph (no spring runoff to cue spawning), habitat degradation from river narrowing and canalization, and construction of diversion dams that prevent migration. Even with the minnow's listing in 1994, its population has continued to drop at a great rate. Minnow numbers are now considerably below their 1994 population, and the Rio Grande silvery minnow is found in only 5% of its former habitat. Alterations of the Rio Grande include not only the modification of the flow of water by dams and channels, but also the unintentional pollution of the water, which can originate from many factors, the major ones being effluents by the military and industrial companies and wastewater from nearby cities and towns.