Refutation of media reports on introduction of the red bellied piranha and potential impacts on aquatic biodiversity in India.

The presence of a new, potentially deadly exotic fish resembling the Red Bellied Piranha, Pygocentrus nattereri was reported in India by print media from various aquatic resources. These reports raised dramatic concerns over public health issues and threats to the aquatic biodiversity of India. Considering the potential severity of the issue and concerns raised by the media, we undertook a study to evaluate the reliability of identification reports of the suspected fish, any relationships to other species of piranha and to address any possible threats to the aquatic biodiversity of India. For this study, samples were collected from most of the major river systems and lakes in India and evaluated for taxonomic identifications of the suspect fish and phylogenetic relationships to other fish species. Our results clearly show that the suspect fish is in fact Piaractus brachypomus, a species commonly referred as "Pacu", and not the red bellied piranha, P. nattereri. Comparisons of both fish do show striking similarities that may account for the misreporting in the media. Furthermore, P. brachypomusas is still an exotic fish, and as such may still have potentially harmful impacts on the native aquatic fauna of India. Quick attention to this issue and the imposition of control measures, including market bans, should be considered to prevent further loss of biodiversity.