Selais fish is difficult to discriminate with other Silurid fish species based on morphological characters. As a result, the valid species of selais fish is uncertain. Therefore, a molecular phylogenetic study was needed to clarify species boundaries and to addresses genetic relationships of the selais fish. In this study, 16S mitochondrial gene of ten selais samples collected from Arut River (Central Kalimantan) were sequenced, from which a Bayesian trees was generated. Result revealed monophyletic of selais fish which is revealed as a single species. The Bayesian inference showed that the selais fish clade is distinguished with two other genus, Kryptopterus and Ompok, by its sequence differences. This finding can address species boundaries of selais fish using Bayesian approach, but the name of the selais species has not been clarified.