Hilsa (Tenualosa ilisha) (in Bengali, Ilish) is the national fish of Bangladesh. It is also known as the ilishi, hilsa, hilsa herring or hilsa shad, which is a species of fish related to the herring, in the family Clupeidae. This highly popular and expensive fish contributes about 12% of the total fish production and about 1.15% of the GDP in Bangladesh. Hilsa is a marine fish but it comes to freshwater during spawning. So far no report has been published on any disease of Hilsa fish. Nothing is known about the gut microbiome of this unique national fish. This study aimed to analyze the gut microbiome of Hilsa fish using next-generation sequencing (metagenomics).