sources, like caves or aquifers), but far more of A. mexicanus (more than 30). Diet and ecology Astyanax aeneus is a voracious omnivore. Its diet includes algae, seeds, leaves, fruit, plant husks, insects (both aquatic and terrestrial, as well as larvae), and fish smaller than it, including fry of any species. In turn, A. aeneus is sometimes a food source for human populations in rural areas, and is also subject to infestation by gill parasites from the flatworm family Monogenea; species include Anacanthocotyle anacanthocotyle, Characithecium costaricensis, Diaphorocleidus kabatai, Palombitrema heteroancistrium, and Urocleidoides strombicirrus. In fact, Diaphorocleidus kabatai was first described from the gills of A. aeneus. Sympatry If other fish in the same environment are too large to be eaten, A. aeneus can live in sympatry with them; most examples are congeners. Closely-related species Astyanax cocibolca lives syntopically with A. aeneus in Lake Nicaragua. A. aeneus and Astyanax caballeroi both inhabit Lake Catemaco, Mexico. (A. aeneus and A. caballeroi, while they are visually distinct and are considered separate species, have little phenotypic difference; early-stage research presents the possibility that the species are synonymous, just different morphs.) Presence and behavior in aquaria Reportedly, A. aeneus is among the various species of Astyanax available for purchase in the aquarium trade, though their presence appears to be sparse. They seem to be acceptable additions to a community aquarium, though only alongside other species that can keep up with its ravenous appetite and rambunctious nature. Their active nature is a part of why they may be appealing. At least one hobbyist report exists of A. aeneus being part of the exhibits in the Shedd Aquarium. Conservation status Astyanax aeneus is considered a species of least concern by the IUCN due to its wide range and generally adaptable nature. Though its range was once wider due to accepted synonymy of species that are now considered separate, its population levels remain high and stable without signs of an imminent decrease or catastrophe. This may change, given its status as a cryptic species; if more speciation is revealed through study, then the range of A. aeneus may shrink as different populations are renamed entirely. However, this is unlikely. References Fish described in 1860 Taxa named by Albert Günther Characiformes Fish of South America Fish of Central America Fish of Mexico Fish of Panama Fish of El Salvador Fish of Guatemala