Vibrio alginolyticus is an important pathogen of marine animals and has been the target of phage therapy applications in marine aquaculture for many years. Here, we report the isolation and partial characterization of a novel species of the Siphoviridae family, the Vibrio phage Artemius. The novel phage was species-specific and could only infect strains of V. alginolyticus. It could efficiently reduce the growth of the host bacterium at various multiplicities of infection as assessed by an in vitro lysis assay. It had a genome length of 43,349 base pairs. The complete genome has double-stranded DNA with a G + C content of 43.61%. In total, 57 ORFs were identified, of which 19 were assigned a predicted function. A genomic analysis indicated that Vibrio phage Artemius is lytic and does not harbor genes encoding toxins and antibiotic resistance determinants.