The Andes Mountains formed along the western margin of South America as a result of tectonic collision and subduction of the Nazca Plate, the floor of the eastern Pacific Ocean, underneath the western South American Plate. Beginning in the Late Miocene, this collision instigated transcontinental changes in topography and hydrology that continue to this day. It also created a vast expanse of tropical high-elevation, fast-water habitat in Andean watersheds from Panama to Bolivia. The biogeographical dispersal, speciation and evolutionary specialization of fishes across these habitats remain poorly understood influences on the diversification of Neotropical organisms. Unfortunately, the great hydroelectric potential of these rivers is now being aggressively exploited with little thought given to the natural ecological function of these rivers or the endemic biodiversity they contain. I have conducted aquatic biodiversity surveys and taxonomic, evolutionary and ecological research in Andean rivers throughout Bolivia, Ecuador, Peru and Venezuela. I am now expanding this research northward into Colombia.