Acantopsis rungthipae is distinguished from all congeners by the combination of the following characters; absence of exposed labial barbels; upper margin of caudal-fin base usually with distinct small black spot; side of head with 0-1 row of large spots; absence of large black spots on dorsal or caudal fins; absence of black specks beneath midlateral row of black spots (rarely present); dorsal fin usually with 9½ branched rays and pectoral fin with 10 rays; 10-20 dark saddles along dorsal midline; 9-17 black spots on side of body; 41-43 total vertebrae; and body depth 9.0-14.2% SL, body width 5.3-10.3% SL, caudal-peduncle length 11.5-16.1% SL (Ref. 116755).