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In recent decades, considerable attention has been devoted to endocrine disruptor chemicals (EDC) and studies on fish feminization have increased throughout the years as a key signal for aquatic environmental contamination. The input of domestic sewage into water reservoirs is common in South American countries, especially in cities that experienced rapid population growths and unplanned urbanization. This study aimed at characterizing morphofunctional parameters of the tropical fish Sphoeroides testudineus and investigating the potential occurrence and effects of endocrine disruptors in the Pacoti River (Ceará, Brazil), often considered a reference site. After collection from the field, fish were measure/weighted and desiccated for gender identification (males, females, and undifferentiated), gonadal histology, and vitellogenin expression. From the biometric analysis, undifferentiated fish showed lower weight and length than female and male fish, although no differences in the condition index were observed. The gonadal weight of undifferentiated fish was significantly lower than those of females and males. Although this pattern was observed, gonadosomatic index (GSI) showed a different pattern, with differences being observed just between males and the other two groups (females and undifferentiated). Vitellogenin (VTG) expression was detected in many mature male and undifferentiated fish, indicating endocrine disruption. In addition, several EDCs (estrone, 17α-estradiol, 17β-estradiol, 17α-ethinylestradiol, diethylstilbestrol, and estriol) were identified and quantified in sediments from the sampling site. These results were unexpected and indicative that the Pacoti River is impaired by estrogenic contamination.