Xenotoca melanosoma Fitzsimons, 1972

Conservation: Xenotoca melanosoma est évalué par l'Union Internationale pour la Conservation de la Nature dans la Liste Rouge des espèces menacées comme étant (EN) en danger (2018). Xenotoca melanosoma is threatened by chemical water pollution caused by agricultural activities (nutrients, herbicides, pesticides, sediments) and waste water discharge from towns and villages. This especially impacts larger river (ríos Ameca and Tamazula) and endorheic lagoons. Furthermore, heavy droughts caused by climate change and the silting up of habitats, mainly in the drainages of the lagoons west of the Chapala lake, lead to a decline in locations and the disappearance of this species from many areas. Introduction of Blue Tilapia and the occurrence of other non-native fish species (Xiphophorus helleri, Sunfish, Pseudoxiphophorus bimaculatus) has resulted in competition for food within these habitats, causing severe declines. In a few spring-fed ponds, recreational activities might cause also declines in stocks, especially when existing riparian vegetation is eradicated (Köck, 2019).

In 2008, it was estimated that the X. melanosoma had experienced a 75% reduction in its historical range (Domínguez Domínguez et al., 2008:505).