The N.E. Region of India is considered as one of the Hotspot of Freshwater Fish Biodiversity in the World. However, there have been drastic reduction in the abundance of freshwater fishes in the region due to many reasons; notably, destruction of habitats, unsustained over-exploitation, dreadful fish diseases like the Epizootic Ulcerative Syndrome (EUS) caused by various pathogens and parasites and other anthropogenic causes. Still further, 'fish' is one of the principal staple food items and rich source of animal protein for the people of fish-eating regions. Lack of a comprehensive treatise on the parasites in fishes in this region has prompted this humble piece of work and the authors will consider themselves to be amply rewarded if this humble piece of work proves to be useful for those it is meant.