Diagnosis: Protomelas krampus differs from most species of Protomelas, i.e. P. annectens, P. fenestratus, P. kirkii, P. labridens, P. macrodon, P. marginatus, P. pleurotaenia, P. similis, P. spilonotus, P. taeniolatus, P. triaenodon and P. virgatus, by having only one inner tooth row, whereas the other species have two rows (Ref. 122325). It can be distinguished from P. spilopterus by a shorter premaxillary pedicel, 17.0-19.2% of head length vs. 21.8-28.4%; a larger gape inclination, 70-80° vs. 40-60°; a shallower body, 33.3-34.3% of standard length vs. 36.0-42.8%; a smaller predorsal distance, 27.4-29.1% of standard length vs. 33.4-37.4%; a smaller prepectoral distance, 29.4-29.8% of standard length vs. 31.8-40.0%; a shorter and more slender head, its length 27.8-29.2% of standard length vs. 30.4-34.6%, and width 39.3-40.3% of head length vs. 41.4-50.7%; and a smaller interorbital width, 22.9-23.4% of head length vs. 25.0-33.6%; in addition, it has more gill rakers on the outer epibranchial than P. spilopterus, 5 vs. 3-4, and more vertebrae, 31-32 vs. 29; the inner teeth are tricuspid in P. krampus while mixed unicuspid/tricuspid or unicuspid in P. spilopterus; the outer teeth of the lower jaw of P. krampus are oriented straight up, whereas those of P. spilopterus are angled forward (Ref. 122325). It differs from P. insignis by a shorter premaxillary pedicel, 17.0-19.2% of head length vs. 27.9-30.0%; a deeper cheek, 31.6-40.2% of head length vs. 23.2-28.5%; the larger gape inclination, 70-80° vs. 30°; a smaller predorsal distance, 27.4-29.1% of standard length vs. 34.2-35.9%; a smaller prepectoral distance, 29.4-29.8% of standard length vs. 32.7-35.4%; a shorter and more slender head, its length 27.8-29.2% of standard length vs. 31.6-34.3%, and width 39.3-40.3% of head length vs. 41.3-44.8%; a shallower lacrimal, 19.6-20.4% of head length vs. 21.4-22.4%; a smaller interorbital width, 22.9-23.4% of head length vs. 26.9-32.8%; and a longer lower jaw, 37.7-38.8% of head length vs. 31.2-37.3%; the upper jaw has fewer outer teeth in P. krampus than in P. insignis, 37-40 vs. 43-50; outer lower jaw teeth are straight in P. krampus but curved inwards in P. insignis (Ref. 122325). It differs from both species of the genus Hemitaeniochromis by its continuous midlateral stripe, which places it in Protomelas, whereas H. urotaenia and H. brachyrhynchus have an anteriorly spotted stripe (Ref. 122325). It differs from the paedophagous species of the genus Caprichromis by its melanin pattern: it has a midlateral band from behind the opercle to the base of the caudal fin, whereas species of Caprichromis have a diagonal stripe from the nape to the base of the caudal fin (Ref. 122325). It differs from Diplotaxodon greenwoodi by the lack of a melanin pattern in the latter species; it has isognathous jaws, whereas D. greenwoodi has a protruding lower jaw (Ref. 122325). Protomelas krampus differs from Naevochromis chrysogaster by its melanin pattern, which consists of three large spots on the lateral sides in the latter instead of a continuous midlateral line; it has a more strongly inclined gape than N. chrysogaster; and it has only one inner tooth row on the lower jaw, whereas N. chrysogaster has two (Ref. 122325).

Description: Body moderately elongate (Ref. 122325). Head profile somewhat steep, clearly concave at eye level; snout above upper jaw convex; mouth very steep, vertically orientated with a gape inclination of 70-80°; premaxillary pedicel small; jaws isognathous; lower jaw long; posterior side of lower jaw protrudes anteriorly; anterior side of lower jaw slightly wider than posterior side; deep chin; larger specimen with larger mouth inclination and deeper chin; lip longer than half length of lower jaw; lips normal; lower lip with mucosa embedding teeth; preopercle also inclined; long and slender gill rakers (Ref. 122325). Outer row of teeth on upper and lower jaws mostly unequally bicuspid and some posterior teeth unicuspid in smaller specimen; anterior teeth exclusively unicuspid on both jaws of larger specimen; teeth straight and not curved inwards; anterior cusps of teeth on outer row in both jaws larger than posterior cusps in smaller specimen; anterior teeth larger than posterior teeth in smaller specimen; one inner row of irregularly placed tricuspid teeth on both jaws in smaller specimen; posterior and inner teeth in larger specimen not readily observable, being to a large extent or fully covered by fleshy gums; teeth closely set, space between teeth about half to one tooth width (Ref. 122325). Pectoral fin origin behind level of dorsal fin origin in smaller specimen; position of pectoral fin origin unknown in larger specimen because of damage; pelvic fin origin positioned slightly more backwards than level of dorsal fin origin; pectoral fin and pelvic fin almost to level of anus; anal fin anterior to level of first soft dorsal fin ray; small scales on base of caudal fin rays (Ref. 122325).

Colouration: In life, body generally greyish; head and pectoral fin base yellowish; pelvic fin with white distal part of leading edge; five orange-brownish eggspots on anal fin; continuous dark midlateral band from about one eye length behind opercle to caudal fin; supralateral row of dark spots; dark spots also present just below dorsal fin; some spots are arranged in an interrupted vertical bar pattern (Ref. 122325). In preserved specimens, body generally brown or greyish; dorsum somewhat darker than belly; darker on dorsal parts of head and body contiguous with dorsal fin base; clear dark maculae on spiny part of dorsal fin, possibly also on soft dorsal fin part and caudal fin; continuous dark midlateral band from one eye length or about three scales behind opercle to caudal fin; one supralateral and one subdorsal row of dark spots; some spots as subtle, incomplete vertical bars; both types currently pale-coloured, probably due to light exposure (Ref. 122325).