Diagnosis: Zaireichthys mandevillei differs from all other members of the genus Zaireichthys, except Z. zonatus, in the small eye, which is 12 times in the head length, compared with the range of 4.1-7.4 in the other species; it differs from Z. zonatus in the shape of the caudal fin, which is forked in Z. mandevillei and rounded in Z. zonatus (Ref. 86935).

Description: Most slender-bodied and perhaps the smallest species of Zaireichthys (Ref. 51287). Entire dorsal surface of head with longitudinally oriented, interrupted ridges; snout more pointed than in other Zaireichthys species; eyes small; barbels attenuate, maxillary barbel extending posteriorly to middle of pectoral fin spine (Ref. 51287). Pectoral fin spine elongate, with 7-9 strong serrae; caudal fin forked, lower lobe larger and longer than upper lobe; number of principal caudal fin rays: 6+5 (Ref. 51287). Caudal peduncle very slender (Ref. 51287). Humeral process very short, without denticulations (Ref. 51287).

Colouration: Colour spotted, with a prominent dark collar just behind head (Ref. 51287).