Etroplus suratensis is known for the high commercial value fish available in South India. The identification of the species of this fish cumbersome and inaccurate in different life stages of the fish. Therefore, DNA sequence of cytochrome Oxidase subunit I gene was analysed for the species identification and phylogenetic relationship of the species. The average genetic distance of conspecifics species value was found to be 0.005%. The present work suggests that COI sequence provides sufficient information on phylogenetic and evolutionary relationship to distinguish the Etroplus suratensis species, the brackish waters species of pearl spots, unambiguously. Further, this work revealed that every species having individual genetic distances depended upon the environmental stress and water quality, which play an important role for its minor morphometric variations. Therefore, it was concluded that a DNA COI barcoding tool can be used for fish identification by non technical personnel (other than taxonomist).__ampersandsignnbsp;