Mayaheros

Mayaheros is a genus of cichlid fish that is native to Mexico and northern Central America. This genus has a disjunct distribution, with the M. urophthalmus group being found in the Atlantic drainages of southeastern Mexico (southern Veracruz east to the Yucatán Peninsula and southwards), Belize, eastern Guatemala, northern Honduras, and northeastern Nicaragua, while M. beani is the northernmost cichlid in the Pacific drainage, ranging from Jalisco to Sonora in northwestern Mexico. Both inhabit a wide range of habitats, such as freshwater rivers, streams, lakes, ponds, pools and marshes, as well as brackish waters including estuaries, lagoons, and mangroves, with members of the M. urophthalmus group sometimes even occurring in caves or coastal marine waters. They are medium-sized to large cichlids that are omnivorous, feeding mostly on small animals, but also plants and detritus.

Mayaheros cichlids are sometimes kept in aquaria and commonly caught for food. Broadstock of the M. urophthalmus group that is better suited for farming is being developed by Mexican authorities; M. beani also has potential in farming, but preliminary tests have been complicated by its high levels of aggression. Both M. beani and M. urophthalmus are overall common and regarded as least concern by the IUCN, although certain local populations are under pressure from habitat loss, pollution, overfishing and introduced species. A captive breeding program exists for a few populations of M. beani. If many species are recognized within the M. urophthalmus group (see #Species), most are restricted to a single location in the Yucatán Peninsula region, such as a lagoon, cenote, cave, island, or bay, and some are seriously threatened. The most threatened –if not already extinct– are likely M. conchitae of the Conchita Cenote and M. ericymba of the Sambulá Cave (M. ericymba has enlarged eyes and sensory pores, likely an adaption to its low-light habitat), which both are located at the city of Mérida. The Conchita Cenote appears to have disappeared entirely, and while the Sambulá Cave still exists, M. ericymba has not been seen since the 1930s. If recognized as valid species or subspecies of M. urophthalmus, these two are the only likely extinct cichlids of the Americas. Conversely, M. urophthalmus has been introduced outside its native range in Oaxaca (Mexico), Florida (United States), the Philippines, Thailand and Singapore. It is unclear which member of the M. urophthalmus group is involved in these introductions, except in Florida where the population was based on individuals from several different locations in the M. urophthalmus group's native range.