The dataset contains records of Fishes (Pisces) collected in the lower valley of River Sabor (NE Portugal) in the scope of the long-term Ecological Monitoring (PME) and Complementary Measures (PMC) Programs of the Baixo Sabor Hydroelectric Dams (AHBS), promoted by EDP – Energias de Portugal, S.A, to evaluate the impacts of dam construction in the fish communities and water quality of the river. This dataset refers to the years of 2015-2020, during the exploration phase. Fishes were captured in 68 sampling points (61 sampling stations by electrofishing, with restitution in lotic habitats, and 7 sampling stations by surface and deep netting (4) and electrofishing (3) in lentic habitats), in the summer of each year. A total of 39443 records of 17 species and one genus were recorded. The most abundant species (>5000 records) were Luciobarbus bocagei (10208 individuals), Pseudochodrostoma duriense (9029) and Alburnus alburnus (7031).