Sundarban is the largest delta on the planet.it covers about one million hector. Sundarban situated in the delta of the river Ganga, Brahmaputra and Meghna and it is famous for his marine and estuarine fish resources. Sundarban shared two country borders- one is India and other is Bangladesh.in sundarban around 440 species of fishes, 20 species of prawn and 44 species of crabs are present. But now a days sundarbans faces lots of difficult problems which have an impact on the biodiversity, sustainability and live hood of fish resources and also natural climate changes such as cyclonic storms, low pressure in bay of Bengal, shrinking tiger pawn population, fish seed collection etc. the present study highlight the present status of fish biodiversity in sundarban and their actual threats.