GOBIIDAE Stigmatogobius sadanundio, 3.8 cm SL (photo by Koichi Shibukawa) Stigmatogobius sadanundio (Hamilton, 1822) Gray Knight Goby D VI + I, 7-8; A I, 7-8; P1 18-21; LR 25-29; PDS 8-10. Body relatively short, compressed. Head slightly compressed; jaws subequal; gill opening not extending anteriorly to a vertical through preopercular margin; anterior margin of tongue rounded. Middle some spines of first dorsal fin elongate, forming tall pointed fin; pelvic fins united medially; frenum present. Scales ctenoid, excepting those on nape, opercle, breast and pectoral-fin base cycloid. Sensory canals and pores present on head; transvers rows of sensory papillae on cheek; a pair of short longitudinal sensory-papillae rows just behind chin. Color: body gray with many black dots, forming some irregular rows; black markings of first dorsal fin behind third spine. Size: 9.0 cm SL. Distribution: Indo-West Pacific. Remarks: found in tidal estuaries and around freshwater area.