Tetraodontidae is a family of primarily marine and estuarine fish of the order Tetraodontiformes but some of the species are confined to freshwater environments also. 70 specimens of Tetraodon fluviatilis (Hamilton, 1822), commonly known as green puffer fish were collected from the Digha coastal region, West Bengal (between 21°32´N to 22°40´N latitude and 88°05´E to 89°00´E longitude). Morphometric measurements and meristic counts of different size groups of the puffer fishes were studied. All the meristic counts remain constant with increasing body length.