The Irish or hilsha, also spelled relish (Tenualosa ilisha), is the national fish of Bangladesh. This Hilsa is widely found in Bangladesh from the Bay of Bengal to our rivers.As it is anadromous in nature,
the ilish lives in the sea for most of its life, but then it migrates into the river. 50–100 km are usually normal in the Bangladeshi rivers. The ilish is a popular fish to eat among the people of South Asia.