Psilorhynchus olliei belongs to the P. balitora species group and is distinguished from all other members by the following combination of characters: 5-6 round to squarish lateral blotches; 6-7 dorsal saddles, all but largest separated from lateral blotches; small dark brown blotches scattered irregularly across scales in L1, L+1 and L+2 scale rows in posterior half of body; obvious row of small dark brown blotches in L-1 row, bordering ventral margin of lateral blotches in posterior half of body; caudal fin with elongate black marking extending along ventral margin of lower lobe; dorsal fin with black stripe across center that is widest anteriorly; 31-32 lateral-line scales; 10 + 9 principal caudal-fin rays; v.9-10.i-ii pectoral-fin rays; 32-33 (16-17+16-17) total vertebrae; anteriormost branchiostegal ray present; parietal portion of temporal sensory canal with 3 openings; preopercular portion of preopercular-mandibular canal with 4 openings; ventral surface between paired fins without scales (Ref. 103424).

Description: Dorsal-fin rays iii.9; anal-fin rays ii.5.i or ii.6; pectoral-fin rays v.9.ii or v.10.i; pelvic-fin rays ii.7 or ii.6.i (Ref. 103424).