Up to the date the best description of the the freshwater fish fauna of El Salvador includes 101 species divided into 64 genera, 29 families, and 14 orders based on the revision conducted by McMahan et al. (2013). However, some fish that occur in freshwater environments (rivers and lakes) can sometimes occupy marine environments, making it difficult to create discrete categories. Recognizing this fact, it is considered that from this 101 species and its potential to tolerate salinity, 73% of these species are peripheral, 23% secondary, and only 4% are primary freshwater fishes McMahan et al. (2013). Posterior research revealed that the only endemic species recorded for El Salvador, the convict cichlid Amatitlania coatepeque was in fact neither endemic nor restricted and belonged to the species Amatitlania nigrofasciata. Nonetheless, some additional peripheral species were recorded recently for Álvarez et al. (2017) in the Acahuapa watershed keeping the number of freshwater species in El Salvador to 101.