Diagnosis: Species with a piscivorous morphology; snout acute in lateral view; outer oral teeth few and large, 25-47; males grey with light blue flank and a dusky to black head; female colour pattern similar to males (Ref. 126312). Amongst piscivorous species from the Lake Edward system, H. glaucus differs from H. latifrons and H. mentatus by a shorter caudal peduncle, caudal peduncle length 13.4-16.1% of standard length vs. 15.7-18.0%; further from H. latifrons by a longer anal fin base, 17.3-20.3% of standard length vs. 14.7-17.3%; and absence vs. presence of a well-defined mid-lateral band; further from H. mentatus by a broader lower pharyngeal bone, lower pharyngeal width 93.3-95.1% of lower pharyngeal length vs. 83.6-85.7%; a slightly longer pre-pectoral distance, 36.4-39.4% of standard length vs. 33.1-38.2%; and dominant males uniformly light blue vs. yellow-green with a red anterior part of flank (Ref. 126312). It differs from H. rex and H. simba by a broader interorbital rea, interorbital width 50.957.1% of head width vs. 44.9-52.7%; further from H. rex by a gentler sloping snout, 30-40° vs. 40-50°; acute vs. rounded oral jaws in dorsal view; and dominant males light blue with a blackish operculum and a dusky snout vs. cream-coloured with an orange operculum and a light blue snout; further from H. simba by a broader lower pharyngeal bone, lower pharyngeal width 93.3-95.1% of lower pharyngeal length vs. 83.8-87.9%; absent or weakly developed vs. strongly developed mental prominence; and dominant males uniformly light-blue vs. yellow with an orange anterior part of flank (Ref. 126312). It differs from H. aquila by the combination of a smaller eye, eye diameter 23.2-28.7% of head length vs. 30.0-31.5%; a narrower head, head width 38.9-40.9% of head length vs. 40.1-43.7%; and dominant males light blue with crimson anal and caudal fins vs. light grey with bright red anal and caudal fins (Ref. 126312). It differs from H. kimondo, H. curvidens, and H. quasimodo by the combination of a narrower head, head width 38.9-40.9% of head length vs. 42.0-48.1%; large vs. small outer oral teeth; and a smaller number of outer upper jaw teeth, 25-47 vs. 43-71; further from H. kimondo and H. quasimodo by dominant males light blue vs. grey dorsally and yellow or blue-black ventrally (Ref. 126312). It differs from H. falcatus by the combination of a shorter predorsal distance, 35.4-37.0% of standard length vs. 36.9-41.1%; a steeper lower jaw side, 35-45° vs. 15-25°; weakly recurved vs. strongly recurved outer oral teeth; and dominant males uniformly light blue vs. olive-green with an orange-red anterior part of flank (Ref. 126312). It differs from H. pardus by the combination of deeper lacrimal, lacrimal depth 18.0-22.7% of head length vs. 16.0-18.3%; a broader interorbital area, interorbital width 50.9-57.1% of head width vs. 39.3-48.4%; and dominant males light blue vs. speckled to uniformly black (Ref. 126312). It further differs from H. squamipinnis by the combination of a gentler gape inclination, 20-30° vs. 30-45°; absence vs. presence of minute scales on proximal parts of dorsal and anal fins; and dominant males light blue vs. slate blue (Ref. 126312).

Description: Body shallow and oval (Ref. 126312). Head long, very narrow, and with a straight dorsal outline; eye small; interorbital area narrow; lacrimal and cheek deep (Ref. 126312). Snout long, rounded in dorsal view, very narrow, acute, and slopes gently at 30-40°; premaxillary pedicel long and weakly prominent; jaws long, relatively stout, narrow, isognathous, and acute in dorsal view; gape large and slopes gently at 20-30°; maxilla extends, almost, to vertical through anterior margin of orbit; lower jaw relatively stout and with a straight to slightly convex ventral outline in lateral view, mental prominence absent or weakly developed, and lower jaw side steep with an inclination of 35-45° to horizontal in anterior view; upper jaw expanded anteriorly and weakly ventrally; lips and oral mucosa large (Ref. 126312). Neurocranium shallow, ethmo-vomerine block decurved, preorbital region shallow, 20-23% of neurocranium lengt, orbital region shallow, 28-31% of neurocranium length, and supraoccipital crest shallow and wedge-shaped (Ref. 126312). Outer oral teeth few, unicuspid, and very large; necks conical, stout, and straight; crowns recurved and acutely pointed; dental arcades rounded; outer teeth widely and irregularly set with neck-distances of 1-4 neck-widths; in upper jaw, 1-3 posteriormost teeth slightly enlarged; inner teeth small, strongly recurved, unicuspid, and acutely pointed; tooth bands very slender crescent-shaped with 1-3 rows of inner teeth, and narrow posteriorly until only outer row remains past 3/4 length of tooth band; inner teeth closely and regularly set on 1-2 outer neck-widths from outer row; implantation recumbent; size decreases slightly buccally and posteriorly (Ref. 126312). Lower pharyngeal bone average in length, triangular, slim, and shallow over whole length; pharyngeal teeth relatively large and slender; major cusps acutely pointed; cusp gaps straight; minor cusps and cusp protuberances mostly absent; teeth in two median longitudinal rows equal in size and form to lateral teeth, 10-12 in each row; posterior transverse row with 15-16 teeth, implanted recumbently with a lateral inclination; major cusps recurved, bluntly pointed, and laterally compressed; minor cusps small (Ref. 126312). Chest scales small; transition to larger flank scales gradual; minute scales on proximal half of caudal fin; scales in longitudinal line 32-37, scales on upper lateral line 21-25, scales on lower lateral line 8-13, scales between dorsal fin and upper lataeral line 5-7, scales between upper lateral line and anal fin 10-15, scales around caudal peduncle 16-20, scales between pectoral and pelvic fins 6-8, infraorbital cheek scales 3-5, postorbital cheek scales 9-12 (Ref. 126312). Caudal fin emarginate; dorsal and anal fins reach to between verticals through one scale anterior to and two scales posterior to caudal-fin base; pectoral and pelvic fins reach to between anal opening and first anal-fin spine; first branched pelvic-fin ray not elongated (Ref. 126312). Ceratobranchial gill rakers in outer row of first gill arch short, stout, and simple; posteriormost rakers anvil-shaped to rarely weakly trifid; epibranchial gill rakers slender and simple (Ref. 126312).

Colouration: Colouration in life of dominant males: flank and caudal peduncle light blue; dorsum grey with a yellow sheen; belly, chest, and operculum blackish with a yellow sheen; flank with 5-7 faint vertical stripes; preoperculum black; cheek black with blue sheen; lacrimal and snout dusky; lower jaw blackish; branchiostegal membrane black; eye with dark grey outer ring and silver inner ring; nostril, interorbital, supraorbital, and lacrimal stripes well-defined; nape band, vertical preopercular stripe, and mental blotch present; operculum with black posterior border; pectoral and dorsal fins hyaline; dorsal fin with black lappets, dusky base, and dusky and maculated crimson posterior part; anal and caudal fins crimson; anal fin with dusky posterior part and 12 large orange egg-spots with dusky rings; caudal fin with dusky base, hyaline posterior part, and crimson maculae (Ref. 126312). Colouration in life of females: strikingly similar to dominant males; body, dorsum, and caudal peduncle grey with a yellow sheen; flanks light blue and with 5-7 faint vertical stripes; belly and chest blackish with a yellow sheen; operculum, preoperculum, cheek, lacrimal, and snout grey; operculum with blue sheen; cheek with black sheen; lower jaw blackish; branchiostegal membrane black; eye with dark grey outer ring and silver inner ring; nostril, interorbital, supraorbital, and lacrimal stripes well-defined; nape band, vertical preopercular stripe, and mental blotch faint; operculum with faint black posterior border; pectoral and dorsal fins hyaline; dorsal fin with black lappets, dusky base, and dusky posterior part; anal and caudal fins yellow with a red sheen; anal fin with hyaline posterior part and 1-2 spots resembling egg-spots; caudal fin with dusky base, hyaline posterior part, and dusky maculae (Ref. 126312). Colouration in life of juveniles: dorsum greyish; belly, chest, operculum, and cheek white; transition gradual; nostril, interorbital, supraorbital, and lacrimal stripes, nape band, and mental blotch faint; pectoral, pelvic, dorsal, and anal fins hyaline; dorsal fin with black lappets and dusky base and posterior part; anal fin with a yellow sheen and 1-2 spots resembling egg-spots; caudal fin dusky and with black maculae and a yellow ventral part (Ref. 126312). Preserved colouration: dorsum brown; belly and chest speckled black; flank dark yellowish and with 6-8 faint vertical stripes; cheek yellow and speckled black; snout dusky; lower jaw and pre- and subopercula black; nostril, interorbital, and vertical preopercular stripes well-defined; lacrimal stripe broad and well-defined; supraorbital stripe and nape band faint; pectoral and anal fins hyaline; anal fin with black lappets, a dusky posterior margin, and 1-2 large egg-spots; pelvic fin black; dorsal fin dusky and with black lappets and a maculated posterior part; caudal fin dorsally dusky, ventrally hyaline, and with a dusky base (Ref. 126312).