Introduction: Parasitism can be used as a highly sensitive monitor to detect changes occurring in degraded habitats and can be an indicator of environmental contamination and environmental health. Objetive: This work aimed to investigate the diversity of parasite species in the area, to verify its potential as an indicator of environmental quality, as well as to analyze biochemical parameters of the water at each collection point. Method: The study area comprises part of the Araguaia river basin, in the Cocalinho-MT region. This region has environments with different levels of anthropic impacts (pasture, agriculture, urban occupation, farm condominiums, native vegetation, etc.), in addition to several connected lakes. Result and conclusion: The average prevalence of Protozoa varied between 7.69% and 41.67%, with an overall average of 21.63 ± 10.95%. The mean intensity ranged from 1 to 3 parasites/parasitized fish, with an overall mean of 2.16 ± 0.58 parasites/parasitized fish. The average abundance ranged from 0.15 to 0.75 parasites/examined fish, with an overall average of 0.46 ± 0.23 parasites/examined fish. The present study found ectoparasitism of Protozoa, Monogenea and Branchiura in specimens of fish in the region of the Araguaia River basin, in Cocalinho/MT.