Strain M8-2T, which was isolated from brackish lake water (Lake Sanaru) in Japan, was characterized for representation of a novel species in the genus Algoriphagus. Cells of strain M8-2T were aerobic, Gram-stain-negative and curved-rod-shaped (0.2-0.5 µm wide and 0.7-1.9 µm long). Strain M8-2T grew optimally at 30 °C, pH 6.5-7.5 and in the presence of 0.5-1.0 % (w/v) NaCl. MK-7 was the sole isoprenoid quinone. The major polar lipids were phosphatidylethanolamine, an unidentified phospholipid and an unidentified polar lipid. The predominant cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0. Phylogenetic analysis based on its 16S rRNA gene sequence showed that strain M8-2T belonged to the genus Algoriphagus and was closely related to Algoriphagus aquatilis A8-7T, Algoriphagus boseongensis BS-R1T, Algoriphagus aquaeductus T4T, Algoriphagus olei CC-Hsuan-617T, Algoriphagusshivajiensis NIO-S3T and Algoriphagus mannitolivorans DSM 15301T with sequence similarities of 96.6-97.4 %. Results of average nucleotide identity (<75 %) and digital DNA-DNA hybridization (<19 %) studies showed that M8-2T was distinct from its phylogenetic relatives. Based on the results of tests for acid production, the predominant cellular fatty acid composition, the DNA G+C content and phylogenetic position, a novel species in the genus Algoriphagus, with the name Algoriphagussanaruensis sp. nov., is proposed for strain M8-2T (=JCM 31446T=LMG 29969T).