Total microbial DNA was extracted from intestinal contents of Scatophagus argus using stool DNA extraction kit. The V3-V4 hypervariable region of bacterial 16S rRNA gene was amplified by PCR with universal primers 338F and 806R. PCR products were purified, quantified, mixed equally to construct paired-end amplicon libraries, and sequenced on Illumina NovaSeq 6000 platform