The genus Rhinogobius is widely distributed across Japan and East Asia, including Japan, comprises amphidromous, fluvial, lacustrine, and land -locked species. Because R. kurodai (Tanaka 1808) an endemic species formerly known as Rhinogobius sp. OR (Tou–yoshinobori species complex), in the Kanto region, central Japan, but recently re –assessed taxonomically, has been less studied from ecological, taxonomic and genetic perspectives than other Rhinogobius species, this study investigated ontogenetic morphological changes in artificially –reared larvae and juveniles of the former, in addition to larval salinity tolerance. Larval salinity tolerance is described for artificially -reared newly -hatched larvae reared in eight tanks (0, 5, 10, 15, 20, 25, 30, and 35 psu). Newly -hatched R. kurodai larvae (3.2 ± 0.1 mm in notochord length) had one or two symmetrical pairs of cupulae, (free neuromast organs), on the trunk around the anus or tail region, such having been previously reported in the genus only from larvae of R. sp. BF, a lacustrine species Nine days after hatching (4.5 mm in standard length: SL), the notochord tip projected upwards, and the second dorsal and anal fin ray were formed. Between eighteen (5.6 mm SL) to twenty-one days (6.4 mm SL), the larvae settled to the bottom of the aquarium tank. At thirty-five days (11.2 mm SL), all fins and scales were formed (juvenile stage). All larvae subjected to salinities of 20 to 35 psu died within three days, evidence (together with than of small sized-eggs and ealy presence of larval cupulae) suggesting that R.kurodai is a lacustrine -type species.