The Amazon molly (Poecilia formosa) is a freshwater fish which reproduces through gynogenesis. This means although females must mate with a male, genetic material from the male is not incorporated into the already diploid egg cells the mother is carrying (except in extraordinary circumstances), resulting in clones of the mother being produced en masse. This characteristic has led to the Amazon molly becoming an all-female species. The common name acknowledges this trait as a reference to the Amazon warriors, a female-run society in Greek mythology. They are native to warm, fresh waters of northeastern Mexico and to the extreme southern parts of the U.S. state of Texas on the Rio Grande and the Nueces River.