An Asian arowana (dragonfish; Scleropages formosus) that had been reared for public exhibition in a private commercial aquarium in Seoul Korea was recently found dead. A bacterial pathogen was cultured from the fish's kidney, identified, and confirmed as Plesiomonas shigelloides, using a Vitek System ® 2, PCR and 16S rRNA gene sequencing. The isolated strain proved resistant to commercial antibiotics and the presence of the tetracycline resistance gene (tetA) was detected via genetic analysis. In this paper, we have described the isolation and identification of P. shigelloides from an Asian arowana reared in a private aquarium in Korea.