The diet of fish is of paramount importance in the regulatory processes of aquatic ecosystems, as it does not denote the availability of food distributed in the habitat as much as the choices made by individuals. This study was carried out in two streams located in the Peixe - Boi river basin / PA, at different stages of anthropization, with the aim of comparing the diet of the ichthyofauna, as well as classifying the species analyzed according to their feeding habits into carnivores, herbivores and omnivores, identifying the origin of the items that these animals feed on, whether they are allochthonous or autochthonous and characterizing how these observations can be made in relation to the fish species present in the streams. The absolute importance of food items can be inferred according to the degree of integrity of the bodies of water. A total of 58 individuals had their stomach contents analyzed, where each item was weighed and identified to the smallest possible taxon, making it possible to calculate their Frequency of Occurrence (Fi), the Volumetric Analysis Index (Vi) and the Absolute Importance Index (AIi).