Akysis bilustris is distinguished from congeners by a combination of the following characters: eye diameter 14.0–17.5% HL; serrae on posterior margin of pectoral spine 2–3 and longer than half width of spine, pectoral fin reaching to or overlapping pelvic-fin base (length 24.5–29.3% SL), adipose-fin base length 14.3–18.3% SL, body depth at anus 11.4–13.8% SL, caudal-peduncle length 19.6–23.4% SL; caudal-peduncle depth 6.7–9.2% SL; caudal fin emarginate, and vertebrae 30–31 (Ref. 87997).