A red, heterotrophic, marine bacterium, designated strain VR1T, was isolated from a sea-water sample collected in the shallow coastal region of Keelung, Taiwan. Cells of the novel strain were facultatively anaerobic, Gram-negative rods that were motile by means of a polar flagellum. The strain grew optimally at 25-30 degrees C and pH 6-7. Growth required the presence of NaCl, the optimal concentration being about 2%. The red pigment produced by the cells was identified as prodigiosin. Strain VR1T grew anaerobically by fermenting glucose and other carbohydrates and producing acids and gases. The strain did not require either vitamins or other organic growth factors for growth. It contained 2-OH-16 : 0 and 3-OH-14 : 0 as the major cellular fatty acids. The DNA G + C content was 45.8 mol%. Phenotypic and chemotaxonomic characterization indicated that strain VR1T represents a novel species in the genus Vibrio. Strain VR1T is phenotypically similar to Vibrio gazogenes. However, the reduction of nitrate to nitrite, the ability to utilize D-arabinose, melibiose and L-glycine as sole carbon sources, the inability to utilize sorbitol as a sole carbon source, resistance to O/129 and susceptibility to erythromycin and novobiocin allow differentiation between V. gazogenes and strain VR1T. The name Vibrio ruber sp. nov. is proposed for the novel species, with strain VR1T (=CCRC 17186T =JCM 11486T) as the type strain.