Taxonomic description and DNA barcoding of a newly recorded Wrasse fish species, Halichoeres timorensis (Perciformes: Labridae) collected from Keelakarai region in Gulf of Mannar, Southeastern India. The mitochondrial cytochrome oxidase subunit I gene (mtCOI) with 656 bp region were sequenced for phylogenetic analysis. Recent studies have revealed that many marine fishes are closely associated with coral reefs. During the present investigation, mt COI gene sequence was used to identify the marine fish Halichoeres timorensis. This is the first report for the availability of this species in Gulf of Mannar, Bay of Bengal and the mt COI sequence was deposited in BOLD database and also in Gen Bank (Accession No: KF422721). The Neighbor-joining method was used for phylogenetic analysis that confirmed the analyzed species were dichotomy relationship with its ancestor species. The pairwise genetic distance calculated the species with eight different closely related species ranged from 0.095 to 0.280%. The length of open reading frame (ORF) was 252. This is the piece of evidence to assist in gene prediction. This study highlights the power of molecular method for species identification and need for an extensive, systematic molecular account of its existing marine ornamental fish biodiversity.