Diagnosis: Distichodus ingae is distinguished from D. affinis, D. altus, D. decemmaculatus, D. noboli, D. notospilus and D. teugelsi by the higher number of lateral line scales, 69-73 vs. 37-46; from D. antonii by the inferior mouth vs. terminal, and the higher number of dorsal-fin rays, 26 vs. 21-25; from D. fasciolatus by the lower number of dark vertical bars, 6-8 vs. 13-20; from D. langi by the lower number of scales between the lateral line and the pelvic-fin base, 10 vs. 12, the lower number of pectoral-fin rays, 19 vs. 21, and the lower number of vertical bars, 9 vs. 13; from D. lusosso by the inferior mouth vs. terminal, and the short snout vs. elongated; from D. maculatus by the absence of dark blotches all over the body; and from D. sexfasciatus by the higher number of dorsal-fin rays, 26 vs. 24-25, the higher number of teeth in the outer row of the upper and lower jaw, 17-18 and 20-21 vs. 12-14 on both jaws, and the greenish body colouration vs. orange-reddish (Ref. 122092). It is distinguished from its most similar species D. atroventralis by having more dorsal-fin rays, 26 vs. 22-24, and longer dorsal fin, 12.0-21.9% of standard length vs. 23.6-24.2%, anal fin, 9.9-15.7% of standard length vs. 16.9-17.5%, and pectoral fin, 14.2-20.5% of standard length vs. 21.6-22.7%; and from D. kasaiensis by having more lateral line scales, 69-73 vs. 57-65, fewer dorsal-fin rays, 26 vs. 27-29, and a longer prepectoral distance, 29.1-30.2% of standard length vs. 21.4-30.0% (overlap due to negative allometry) (Ref. 122092).

Description: Body elongated and laterally compressed; dorsal profile convex from tip of snout to end of dorsal-fin base, straight between dorsal and adipose fins, and concave between adipose and caudal fins; ventral profile straight from tip of snout to level of posterior eye border, concave afterwards until end of anal-fin base, and convex between latter and caudal fin (Ref. 122092). Mouth inferior (Ref. 122092). Caudal peduncle slightly deeper than or equal to its length (Ref. 122092). Dorsal fin with straight to slightly convex distal margin; dorsal fin origin well in front of pelvic-fin origin; adipose fin at equal distance from dorsal and caudal fins; only proximal half of adipose fin scaled; anal fin with slightly concave distal margin; length of pectoral- and pelvic-fin rays decreasing from last unbranched ray to last branched ray; distal tip of pectoral fin passing vertical through dorsal fin origin; tip of pelvic fin in close proximity of anterior border of vent; caudal fin forked, lobes pointed; upper lobe slightly larger than lower lobe; only anteriormost fifth to fourth covered with small scales (Ref. 122092).

Colouration: Colouration of preserved specimens: overall body colour light yellowish brown with lighter belly; nine continuous backish vertical bars on flanks; unknown whether vertical blackish bars disappear in larger specimens; distinct black spot in middle of caudal peduncle; dorsal fin with whitish-greyish rays connected with translucent membranes, with scattered small, blackish melanophores of irregular size; proximal half of adipose fin with same colour as body, distal half translucent, without blackish outer edge; pelvic fins darker than basic colour, especially at distal tips; pectoral fins whitish at their base and more translucent distally; anal fin whitish, darker at its distal end; caudal fin light yellowish to transparent (Ref. 122092).