Diagnosis: The moderately-sloped vomer, 43.1°, with a swollen rostral tip, bicuspid teeth in the anterior portion of the outer row of both upper and lower jaws, the lower jaw at a 45° angle to a line from the tip of the snout to the hypural plate, a lower jaw that is slightly longer than the upper, and its feeding at a 90° angle to the substrate place this species in Maylandia (Ref. 127491). The lack of conspicuous vertical bars on the flank and the dark submarginal band in the dorsal fin of male Maylandia koningsi distinguish it from all other species of Maylandia, except M. usisyae; males of M. usisyae have a gold-coloured flank while this is blue in male M. koningsi (Ref. 127491). Females of M. koningsi are entirely brownish yellow and thus distinguished from those of most other species of Maylandia, except for females of M. flavifemina and M. phaeos; the snout of the latter species is relatively longer than that of M. koningsi, 37.9-44.7% of head length vs. 26.6-33.1%, but females of M. flavifemina cannot reliably distinguished from those of M. koningsi apart from the fact that they have a larger size, maximum 79 mm standard length vs. 49 mm standard length for M. koningsi (Ref. 127491).

Description: Dorsal fin with 17-18 spines and 7-9 rays; anal fin with 2-3 spines and 7-8 rays (Ref. 127491). Lateral line with 30-32 ctenoid scales with 1-2 pored scales posterior to hypural plate; cheek scale rows 3-4 (Ref. 127491). Caudal fin emarginate (Ref. 127491).

Colouration: Head of males grey with two bright interorbital bars; cheek with grey markings; gular dark grey/black; laterally light blue dorsally and dark blue/black ventrally; dorsal fin light blue with dark submarginal band and light blue/white lappets; caudal-fin membranes blue, rays pale orange; anal fin black with 1-2 yellow ocelli; tips of rays light blue; pelvic fins with blue leading edge; anterior membranes black fading to clear; pectoral fins with black rays and clear membranes (Ref. 127491). Head of females yellow/brown with 1 light brown/green interorbital bar; cheek yellowish brown with yellow/brown operculum with green highlights; dark grey opercle spot; gular yellow; laterally yellow/brown ground colour with yellow scale margins; centre of scales pale blue/white; belly and breast white; dorsal fin yellow/brown with yellow lappets; distal one-third of rayed membranes bright yellow/orange; caudal-fin membranes yellowish brown with yellow rays; proximal one-quarter of anal fin clear; distal three-quarters yellow orange; pectoral fins with brown rays and clear membranes; anterior three membranes and rays of pelvic fin bright yellow/orange; posterior membranes and rays clear (Ref. 127491).