Exotic fish are a threat to river ecosystems, but what happens when invasive species are native to a territory and have been introduced into waters that are not their original territory? A new study carried out by the UB and published in the journal Science of The Total Environment, has analyzed the impact the native fish receive from these species, called translocated species, compared to the effects of exotic invasive species, i.e, those that are not native to any basin in the territory. The conclusions of the study show that the quality of the habitat is the most important factor for the well-being of native fish, but the study also points out that translocated species can become as problematic as the exotic ones.