Pseudogobius fulvicaudus Huang, Shao & Chen, 2014(Fig 3J; Table 2)Material examined. USMFC (113) 00038, 4 ex., 6.8–11.6 mm SL, Pantai Acheh Mangrove Forest–Site 1, coll. Tan Y.Y., June 30, 2024; USMFC (113) 00039, 13 ex., 15.0–17.5, Pantai Acheh Mangrove Forest–Site 2, coll. Tan Y.Y., July 6, 2024; USMFC (113) 00045, 3 ex., 15.0– 18.4 mm SL, Pantai Acheh Mangrove Forest–Site 1, coll. Tan Y.Y., August 3, 2024; USMFC (113) 00048, 7 ex., 11.5–18.2 mm SL, Pantai Acheh Mangrove Forest–Site 2, coll. Tan Y.Y., September 8, 2024; USMFC (113) 00057, 3 ex., 9.9–14.1 mm SL, Pantai Acheh Mangrove Forest–Site 1, coll. Tan Y.Y., September 28, 2024; USMFC (113) 00066, 3 ex., 8.8–18.3 mm SL, Meromictic Lake, Penang National Park, coll. Tan Y.Y., October 26, 2024; USMFC (113) 00075, 30 ex., 13.7–20.4 mm SL, Sungai Burung Mangrove Forest–Site 2, coll. Tan Y.Y., January 2, 2024; USMFC (113) 00096, 1 ex., 21.3 mm SL, Sungai Betung, coll. Tan Y.Y., March 1, 2025.Description. D1 VI; D2 I,7; A I, 6–7; P 15; LS 24–26; TRB 7–8; PDS 7. Head rounded; snout rounded. Mouth subterminal, oblique, upper lip and snout anteriormost; jaw reaching back to below posterior half of eye. Head pores present; sensory papillae in longitudinal pattern. Body slender, rounded anteriorly, more compressed posteriorly. Predorsal area covered with cycloid scales, extending anteriorly to approximately posterior of eyes, several larger scales behind eyes; cheek naked; opercle scaled. Prepectoral area naked, prepelvic area and belly covered with cycloid scales; body scales ctenoid to behind pectoral fin. First dorsal fin triangular, second spine longest; second dorsal fin low, pointed posteriorly; anal fin low, pointed posteriorly; pectoral fin oval; pelvic fin oval; caudal fin rounded. Head and body pale yellow, white ventrally to anal fin origin with four black spots initiate from anal fin origin to caudal peduncle; short, black bar extended ventrally from eye margin towards posterior jaw margin; lips with narrow dark brown margin; ventral part of opercle blueish; trunk with shoulder bar below first dorsal fin, 4–5 black bars along midline; first dorsal fin translucent, single yellow inframarginal band, single black spot position between fourth to sixth spine; second dorsal translucent grey, single faint yellow broad inframarginal band; anal fin translucent, white margin; pectoral fin translucent; pelvic fin white; caudal fin transparent to translucent, caudal fin base yellow with a pair of black spots.Habitat. Shallow water puddles with sandy–muddy substrates in mangrove forest areas.