larger broods in warm (approximately ) water that provides an overabundance of food. The Amazon molly has been reproducing asexually for about 100,000-200,000 years. This is about 500,000 generations of Amazon molly. Asexual lineages typically go extinct after 10,000-100,000 generations. There is research being done to determine how the Amazon molly has not gone extinct or developed a Muller's ratchet of mutations. Researchers believe the answer is in the genome of the Amazon molly, yet more research must be done to determine this. P. formosa is a hybrid species and P. mexicana is one of the parental species. Its other progenitor is most likely an extant, as yet undescribed, subspecies of P. latipinna or an extinct ancestor of P. latipinna. References No sex for all-girl fish species BBC News, 23 April 2008 Heubel, Katja U.: Population ecology and sexual preferences in the mating complex of the unisexual Amazon molly Poecilia formosa (Girard, 1859).Hamburg, University, Diss., 2004. Poecilia Freshwater fish of Mexico Freshwater fish of the United States Fish hybrids Live-bearing fish Ovoviviparous fish Vertebrate parthenogenesis Fish described in 1859 Taxa named by Charles Frédéric Girard