Abstract
The freshwater aquatic biodiversity is depleting alarmingly due to the introduction of exotic species and other anthropogenic activities. The indiscriminate transfer of exotic fishes has brought about a wide array of problems including extirpation of indigenous species. The exotics compete with the indigenous species for food, habitat and may even prey upon them, introduce new parasites and diseases, result in the production of hybirds and cause genetic 'erosion' of indigenous species and degradation of the physico-chemical nature of aquatic ecosystems. The potential risks not only affect the biodiversity, but also the socio-economic aspects of the human community that depend on aquatic ecosystem for their sustenance. The paper reviews the impact of exotic fishes on aquatic biodiveristy in India and the measures to check this.