The Koshi river which forms the major landmark of the Nepalese geography is the home of 80 fish species. The endangered Gharial crocodile and Gangetic dolphin are also found here. Koshi is an exclusive reserve for the last surviving population of wild buffalo or arna in Nepal. Its number at present is estimated to be 150. The reserve is a habitat of 20 other animal species such as hog deer, spotted deer, wild boar, blue bull and rock python.

Spotted Dear	Hug Deer
Wild Boar	Blue Bull
Wild Water Buffalo	Elephant
Fishing Cat	Gharial
Gangetic Dolphin	Leopard