the biodiversity of fishes and their distribution by municipality and basin in the santander department are presented. a total of 115 native species distributed in eight orders and 34 families inhabit the santander department. the most diverse order is siluriformes with 55 species and 27 genera, and characiformes with 40 species and 28 genera. at the family level, characidae (22 species) and locariidae (14 species) have the greatest numbers of species. the río sogamoso and río lebrija system show the highest diversity (84 and 74 species, respectively). a total of 13 endemic or restricted species in santander were identified in this study.