A polyphasic taxonomic study was performed on a novel strain designated as 04OKA-3-121T, which was isolated from the hard coral Galaxea fascicularis L. collected at Akajima, Okinawa, Japan. These bacterial cells were observed to be pale-yellow, Gram-stain-negative, strictly aerobic, chemoheterotrophic, non-spore forming, non-motile, and rod-shaped. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the novel marine isolate is affiliated with the family Flavobacteriaceae of the phylum Bacteroidetes and that it shared the highest (93.6%) sequence similarity with Pseudozobellia thermophila KMM 3531T. The strain could be phenotypically differentiated from related members of the family Flavobacteriaceae. Major fatty acids of strain 04OKA-3-121T were iso-C15:0, iso-C15:1 G, and C16:1 ω7c and/or C16:1 ω6c. The DNA G + C content of the strain was determined to be 38.8 mol% and the major respiratory quinone was identified as menaquinone 6 (MK-6). Strain 04OKA-3-121T had phosphatidylethanolamine, two unidentified aminolipids, and eight unidentified lipids as polar lipids. From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, the strain is considered to represent a novel genus in the family Flavobacteriaceae, for which the name Coraliitalea coralii gen. nov., sp. nov. is proposed. The type strain of C. coralii gen. nov., sp. nov. is 04OKA-3-121T (= KCTC 52378T = NBRC 112329T).