RESUMEN
The data presented in this article are related to the research article entitled "Competition from sea to mountain: interactions and aggregation in low diversity monogenean and endohelminth communities in twospot livebearer Pseudoxiphophorus bimaculatus (Teleostei: Poeciliidae) populations in a neotropical river." accepted for publication in Ecology and Evolution. The data describes the communities of helminth parasites in 11 populations of a small poeciliid freshwater fish Pseudoxiphophorus bimaculatus (Heckel, 1848) sampled along the La Antigua river basin in Veracruz, Mexico. We examined 19 P bimaculatus from one locality, 21 from another locality, and 20 from each of the other nine locations sampled in June 2016. A total of 220 individual fish were examined, and in this paper we provide the data for 18 helminth parasite taxa recorded from them. The material in this Data paper comprised the raw data on the abundance, i.e. the number of helminth individuals of each of 18 taxa found in each one individual of P. bimaculatus from each of 11 localities. The data set is contained in a single text-table including one matrix containing each of the 220 host P. bimaculatus examined from 11 localities (lines). Measures for each host P. bimaculatus include total length, standard length, maximum deep and sex, documented for everyone fish examined, plus data of the number of individual helminth of each taxa collected by each examined fish are placed in the columns. These data might be used to examine spatial distribution of helminth parasite taxa. These data might be reused to examine the spatial variation in community structure of helminth parasites of freshwater fish. This kind of data could be used to provide an assessment of human environmental impacts, or for public awareness of conservation objectives.