Diagnosis: Bathyaethiops flammeus is distinguished from all congeners by the presence of a spot lacking melanophores, located in front of the dorsal fin, and which is red in life, white in preservation (Ref. 110423).

Description: Body laterally compressed, moderately elevated, maximum size 42 mm standard length (Ref. 110423). Dorsal fin originating at midbody; pelvic fins originating slightly in front of dorsal fin; anal fin originating at level of, or slightly caudal to, end of dorsal-fin base (Ref. 110423). Scale cover complete; lateral line usually incomplete,sometimes complete; when incomplete, number of pored scales in anterior section variable, 5-16; sometimes pored scales also present posteriorly after an interruption of varying extent; 7-10 pre-dorsal scales, but without scales immediately in front of dorsal-fin origin (Ref. 110423). Premaxilla with two teeth in outer row, first with three and second with five cusps, and four teeth in inner row with four to five cusps on first, seven cusps on second and third and five cusps on last tooth; dentary with four teeth in outer row with seven cusps on second, six cusps on first and third, and four cusps on last tooth; an inner single monocuspid tooth close to symphysis present (Ref. 110423). Pectoral fin with 11-12 rays; pelvic fin with 9 rays; 2 hypurals in lower lobe and 4 hypurals in upper lobe; 3 epurals; small cartilage present in front of anterior-most haemal spine (Ref. 110423). Supraneural directly in front of the first dorsal pterygiophore well developed or sometimes completely absent (Ref. 110423).

Colouration: In life: body silvery, slightly translucent; anterior half of dorsal fin and the melanophore-free area in front of dorsal fin bright red; rest of dorsal fin, adipose fin and caudal fin grey; pectoral, pelvic and anal fin transparent; anterior distal part of anal fin black marked in males; upper half of adipose fin black in most specimens; a prominent dark humeral spot smaller than pupil and an extensive black blotch on the caudal peduncle; the latter is bisected by a dark line along the horizontal septum starting slightly behind humeral spot and continuing to the end of the caudal peduncle; about 7-10 more or less regular vertical bars along the horizontal line with most bars located dorsally from the level of the midbody; a dark line from the lower jaw over along the mid-dorsal line on the back to the end of caudal peduncle, with a prominent spot free of any melanophores in front of dorsal-fin base; base of anal fin darkly pigmented, more prominent anteriorly; a prominent dark bar on the end of the caudal peduncle broadened medially; distal edge of adipose fin often black or dark grey, rest of fin slightly grey or colourless; melanophores densely set on upper half of skull (Ref. 110423). In preservative: pale yellow to brownish, all prominent red colouration vanished; the melanophore-free spot in front of the dorsal fin appears clear white; upper half of flank darker; melanophore pattern less pronounced, but better visible as in life specimens; black mid-dorsal line less prominent; black mark along anal-fin base well visible in anterior part as in posterior part, where it is sometimes missing; this line not confluent with blotch on caudal peduncle (Ref. 110423).