The Union Ministry for Agriculture has ordered killing of the predatory fish piranhas which are being clandestinely bred in different parts of the country for aquariums. Under the law, exotic fish varieties need the approval of the National Committee on Introduction of Exotic Aquatic Species in Indian Waters. The panel, consisting of the Fisheries Development Commissioner and other expers, studies the necessity and relevance of the species sought to be introduced and the impact it may have on the Indian aquatic system.