Diagnosis: Species with a piscivorous morphology; body rather deep, body depth 32.4-39.3% of standard length; oral jaws very long, lower jaw length 47.8-58.6% of head length, narrow, lower jaw width 32.6-44.7% of lower jaw length, and steep, gape inclination 30-45°; outer oral teeth many and small, 39-79; dominant males slate blue (Ref. 126312). Amongst piscivorous species from the Lake Edward system, Haplochromis squamipinnis differs from all by presence vs. absence of minute scales on proximal part of dorsal fin, rarely few scales present in H. quasimodo (Ref. 126312). It further differs from H. latifrons and H. mentatus by the combination of small vs. large outer oral teeth, a larger number of outer uppr jaw teeth, 39-79 vs. 22-47; a steeper gape, 30-45° vs. 15-30°; and a deeper body, body depth 32.4-39.3% of standard length vs. 27.2-32.3%; from H. mentatus by dominant males uniformly slate blue vs. yellow-green with a red anterior part of flank (Ref. 126312). It further differs from H. rex, H. simba, H. glaucus and H. aquila by the combination of small vs. large outer oral teeth, a larger number of outer upper jaw teeth, 39-79 vs. 22-47; and dominant males uniformly slate blue vs. cream-coloured with an orange operculum, yellow with an orange anterior part of flank, light blue with a dusky to black head, or light grey with a black head, respectively; further from H. rex, H. simba and H. glaucus by a steeper gape, 30-45° vs. 15-30°; further from H. aquila by a smaller eye, eye diameter 23.1-29.7% of head length vs. 30.0-31.5% (Ref. 126312). It further differs from H. kimondo by a concave to straight vs. convex dorsal outline of head, a gentler snout inclination, 30-40° vs. 40-50°, and dominant males slate blue vs. grey dorsally and yellow ventrally; further from H. falcatus by a shorter head, head length 35.1-36.9% of standard length vs. 36.6-39.6%, and dominant males slate blue vs. olve-green with an orange-red anterior part of flank; further from H. curvidens and H. pardus by a deeper cheek, cheek depth 24.9-36.0% of head length vs. 20.8-24.9%; further from H. pardus by a larger adult size, maximum size 211 mm standard length vs. 96 mm, and colour pattern of small specimens less than 100 mm standard length light coloured vs. speckled to uniformly black (Ref. 126312). It differs from H. quasimodo by the combination of a broader interorbital area, interorbital width 48.6-55.6% of head width vs. 40.5-48.7%; a longer lower jaw, lower jaw length 47.8-58.6% of head length vs. 44.2-49.6%; a steeper gape inclination, 30-45° vs. 20-35°; and dominant males slate blue vs. light grey dorsally and blue-black ventrally (Ref. 126312).

Description: Body average in depth in comparison to generalised Haplochromis elegans, but deep for a piscivorous species, and oval to rhomboid (Ref. 126312). Head long, narrow, and with a straight to concave dorsal outline; eye small; interorbital area narrow; cheek and lacrimal deep (Ref. 126312). Snout long, acute, and slopes very gently at 30-35°; premaxillary pedicel very long and prominent; jaws isognathous to strongly prognathous, slim, very narrow, and rounded in dorsal view; upper jaw long and lower jaw very long; gape large and slopes steeply at 30-45°; maxilla extends to between verticals through anterior margins of orbit and pupil; lower jaw shallow and with a straight ventral outline in lateral view, mental prominence weakly or strongly developed, and lower jaw side steep with an inclination of 35° to horizontal in anterior view; upper jaw expanded slightly anteriorly and ventrally; lips and oral mucosa thin (Ref. 126312). Neurocranium average in depth, ethmo-vomerine block horizontally inclined, preorbital region shallow, 19-25% of neurocranium length, orbital region average in depth, 28-32% of neurocranium length, and supraoccipital crest deep and pyramidical or weakly wedge-shaped (Ref. 126312). Outer oral teeth numerous, unicuspid, and small; necks stout, conical, and straight; crowns weakly recurved in lower jaw, recurved in upper jaw, and acutely pointed; dental arcades rounded; outer teeth closely and regularly set with neck-distances of 1/2-1 neck-width; in upper jaw, 1-3 posteriormost teeth sometimes slightly enlarged; inner teeth small, weakly recurved, unicuspid in large specimens of more than 120 mm standard length; tri- to rarely unicuspid in upper jaw and uni- to weakly tricuspid in lower jaw of small specimens of less than 120 mm standard length, and acutely pointed in all specimens; tooth bands very slender crescent-shaped with 1-3 rows of inner teeth, and narrow posteriorly until only outer row remains past 2/3 length of tooth band; inner teeth closely and regularly set on 1-3/2 outer neck-widths from outer row; implantation recumbent; size uniform throughout tooth band (Ref. 126312). Lower pharyngeal bone long, narrow, slim, and shallow with a slightly deeper keel; pharyngeal teeth relatively large and slender; major cusps acutely pointed; cusp gaps nearly straight; minor cusps and cusp protuberances small; teeth in two median longitudinal rows equal in size and form to lateral teeth, 11 in each row; posterior transverse row with 17-18 teeth, implanted erectly with a lateral inclination; major cusps nearly straight, bluntly pointed, and laterally compressed; minor cusps mostly present (Ref. 126312). Chest scales small; transition to larger flank scales gradual; basal parts of membranes of dorsal and anal fins covered by minute, ellipsoid scales; between some pairs of fin rays, up to two rows of 1-10 scales extend from body onto fin; scales very variable in distribution and density and mostly invisible to naked eye; no scales present anteriorly of fourth dorsal-fin spine; minute scales on proximal half of caudal fin; scales on longitudinal line 30-34, scales on upper lateral line 17-22, scales on lower lateral line 9-19, scales between dorsal fin and upper lateral line 5-7, scales between upper lateral line and anal fin 10-14, scales around caudal peduncle 16-20, scales between pectoral and pelvic fins 4-6, infraorbital cheek scales 3-5, postorbital cheek scales 8-11 (Ref. 126312). Caudal fin emarginate to weakly subtruncate; dorsal and anal fins reach to between verticals through caudal-fin base and two scales posterior to this vertical; pectoral fin reaches to between first and third anal-fin spines; pelvic fin reaches to between first and third anal-fin spine in females, to third anal-fin branched ray in males; first branched pelvic-fin ray elongated in all specimens (Ref. 126312). Ceratobranchial gill rakers in outer row of first gill arch short, relatively slender, and simple; posteriormost rakers sometimes anvil-shaped or weakly bifid; epibranchial gill rakers slender and simple (Ref. 126312).

Colouration: Colouration in life of dominant males: body and head uniformly slate blue; belly and chest black; flank with very faint mid-lateral band and 5-7 vertical stripes in some specimens; snout dusky; lacrimal stripe and mental blotch present; eye with (dark) grey outer ring and silver to golden inner ring; pectoral fin dusky; pelvic fin black; caudal fin crimson and with dusky base and maculated dorsal part; dorsal fin dusky and with black lappets and, in posterior part, maculated crimson; anal fin crimson and with black lappets, a dusky base and posterior part, and 3-4 large orange egg-spots, i.e., twice distance between rays, with hyaline rings (Ref. 126312). Non-dominant males with body and head yellow-green; chest and belly white (Ref. 126312). Colouration in life of females and juveniles: dorsum and dorsal part of head golden; belly, chest, operculum, and cheek white; transition gradual; snout and lower jaw dusky; lacrimal stripe faint, mental blotch present; eye with (dark) grey outer ring and silver to golden inner ring; flank with a very faint mid-lateral band and 5-7 vertical stripes in some specimens; pectoral, pelvic, anal, and caudal fin yellowish; anal fin with hyaline base, dusky distal part, and 3-4 spots resembling egg-spots; caudal fin with dusky distal part and maculated dorsal part; dorsal fin dusky and with black lappets (Ref. 126312). Preserved colouration: dorsal part of body dusky brown, ventral part of body white, transition gradual; in dominant males, belly and chest black; flank rarely with a very faint mid-lateral band and very faint 5-7 vertical stripes; cheek light yellowish; snout dusky; nostril, interorbital, lacrimal, and vertical opercular stripes faint; mental blotch present; lacrimal stripes present in dominant males; pectoral fin dusky; pelvic fin yellowish with dusky distal parts in females, black in males; caudal fin dusky and with black distal margin; dorsal fin dusky and with black lappets and posterodistal margin; anal fin dusky and with a black posterodistal margin, a white base in females, a dark base and 2-3 egg-spots in males (Ref. 126312).