Prochilodus nigricans is extensively exploited in fishing and aquaculture activities in the Brazilian Amazon, it is the definitive host for Neoechinorhynchus curemai Noronha, 1973. Thus, the present study aimed to evaluate the occurrence of N. curemai in P. nigricans and the parasite-host relationship in three rivers (Juruá, Crôa and Môa) in the municipality of Cruzeiro do Sul, state of Acre, Brazil. Fish were caught, weighed, measured, and subjected to necropsy, and the gastrointestinal tract and viscera were analyzed. A total of 178 specimens of N. curemai were found in 61 infected fish, with the (p= 58.62%). The prevalence, mean intensity, and mean abundance were higher in hosts from the Môa River, and lower from the Juruá River. Regarding the length-weight relationship, the b-value did not differ statistically from three (b=3) for fish species in the three locations, nor in parasitized and non-parasitized species. In addition, growth was considered isometric, and in the case of the relative condition factor, there was no difference in fish hosts between the three rivers. The correlation between parasite intensity, condition factor, length, and weight of P. nigricans was not significant. Thus, this parasite infestation varied between the habitats. However, this did not influence the growth and development of the hosts.