The principal aim of this study was realize a helminthological register of the species founded in ornamental fishes cultured in three fish farms and wild fishes existent in the effluents close to these farms in Morelos State, Mexico and an analysis and comparation of the infection values and their relative importance of helminth species invaders associated to ornamental fish industry and their manifestation in wild fishes close to farms. The helminth parasites of freshwater fishes of commercial fish farms, in Morelos State, Mexico were analysed. A total of 419 organisms of six freshwater fish species were collected in three fish farms and in small streams adjacent, in rainy and dry seasons. A total of 40 528 helminth were collected; the metacercarian of the flatworm Centrocestus formosanus affected largest number of host species. There were high levels of infection in all fish for this fluke, specifically for the Mexican molly, Poecilia sphenops it was also found in the native poeciliid fish the Asian tapeworm Botriocephalus acheilognathi, although with lower values in the parameters of infection. A non-deteriorated environment allowed complete the life cycles of parasites, permitting the establishment and maturation in various native and exotic fishes favoured the lack of host specificity of helminths and allogeneic generalists.