Taxonomy & naming
Haplochromis altigenis was described by the British ichthyologist Charles Tate Regan in 1922, in his account of the cichlid fishes of Lake Victoria published in the Proceedings of the Zoological Society of London. The type series came from Bujako (Bunjako) in the Ugandan waters of the lake; Peter Humphry Greenwood later designated a lectotype, BMNH 1906.5.30.294, held with a paralectotype at the Natural History Museum in London (Greenwood, 1967). Regan placed the species in Haplochromis, the vast catch-all genus Hilgendorf had erected in 1888 for African mouthbrooders with simple, unnotched teeth, and that is the heading under which the fish is still most often listed. Greenwood redescribed altigenis in 1967 as part of his long campaign to break the unwieldy Lake Victoria Haplochromis into smaller, ecologically coherent genera, and in his 1980 generic revision he assigned it to Harpagochromis, his genus for large-mouthed piscivores. Later workers have not all followed him: van Oijen and colleagues (1991), reviewing the piscivorous haplochromines, noted that altigenis retains a curved preorbital profile, a deep preorbital and a broad otic region of the neurocranium that align it as much with species Greenwood put in Prognathochromis (such as Haplochromis bayoni and Haplochromis pseudopellegrini) as with Harpagochromis. The genus-level placement of Lake Victoria's piscivores remains genuinely unsettled, and most current databases — FishBase and the Catalog of Fishes among them — conservatively retain the name in Haplochromis pending a comprehensive revision of the flock.
Morphology
Haplochromis altigenis is a moderately large haplochromine by Lake Victoria standards, reaching about 8 in in standard length, which makes it one of the bigger members of the predatory guild. The body is fusiform — elongate and only modestly compressed — the build of an active mid-water hunter rather than a deep-bodied rock-grazer. Its defining feature, and the source of its name, is the cheek: the preorbital (the bony region below and in front of the eye) is unusually deep, described in the original material as considerably greater than the diameter of the eye in a roughly 8.5 in specimen. The mouth is large with a prominent premaxillary pedicel, and the oral teeth are relatively stout and only weakly curved. In his diagnostic comparison FishBase, following the work of de Zeeuw and colleagues, separates altigenis from the superficially similar Haplochromis vonlinnei by its more prominent premaxillary pedicel, much deeper cheek and less strongly curved teeth. Crucially, the live coloration of Haplochromis altigenis is unknown — it was described and redescribed from preserved museum specimens, and no record exists of how breeding males or wild fish actually looked in life. Like other Lake Victoria haplochromines it would have been a maternal mouthbrooder with sexual dichromatism, the males in nuptial dress more vividly coloured than females, but for this species the details simply were never documented.
Habitat
The species is endemic to Lake Victoria, the great shallow equatorial lake shared by Uganda, Kenya and Tanzania, and was not recorded from the satellite lakes (Kyoga, Nabugabo) that hold some other members of the flock. Within the lake it occupied sheltered gulfs and bays and relatively undisturbed offshore water, ranging over both hard and soft bottoms, and FishBase gives a depth range extending to about 52 ft — the sub-littoral and shallow open-water zone rather than the deepest parts of the basin. As a benthopelagic predator it would have hunted through the water column above these substrates. Lake Victoria itself is a warm, alkaline water body: surface temperatures typically run in the mid-20s Celsius, and the water is well-buffered and basic, with pH characteristically around 7.2 to 9.0 across the lake. No in-situ chemistry was measured specifically for altigenis, and the figures used here are the general parameters documented for the lake's open and inshore waters rather than readings from a known capture site.
Feeding
Haplochromis altigenis was a piscivore — a fish-eater — and one of the more committed members of that guild in Lake Victoria. The direct evidence is its gut contents: of the specimens examined, the stomachs held mainly finely macerated fish remains, identifiable as cichlids (the lake's own haplochromines being by far the most abundant prey available). FishBase estimates a trophic level of about 4.2, near the top of the range for the flock and consistent with a predator that fed largely on other fish. The deep cheek, large mouth and stout, weakly recurved teeth all fit this role, allowing it to seize and hold struggling prey. In the pre-perch lake, predators like altigenis were one link in an astonishingly fine-grained partitioning of resources: the haplochromine flock had radiated into algae-scrapers, snail-crushers, insect-pickers, plankton-feeders, scale-eaters, paedophages and piscivores, and the fish-eaters themselves were further divided by where and how they hunted. Haplochromis altigenis represented the bay-and-sublittoral piscivore niche within that system.
Mating
No courtship or pair-formation behaviour has been observed in Haplochromis altigenis specifically — the species was never studied alive in any detail, and its live colours are unknown. What can be said is drawn from the biology of the Lake Victoria flock as a whole, to which it certainly belonged. These are polygynous maternal mouthbrooders: males establish and defend temporary courtship territories, display to females in vivid nuptial colour, and play no part in care once spawning is over. Female mate choice, guided heavily by male coloration under the clear water that once prevailed in the lake, is thought to have been a central engine of the flock's explosive speciation, with closely related species kept reproductively distinct largely by differences in male nuptial dress. For altigenis the relevant behaviours were never recorded, so any account of its mating must be read as the genus-typical pattern rather than direct observation.
Breeding
Like all Lake Victoria haplochromines, Haplochromis altigenis was a maternal mouthbrooder: the female takes the fertilized eggs into her mouth and broods them there, the developing young completing their early life inside the buccal cavity and being released as free-swimming fry, with no male involvement after spawning. No spawning of this particular species has ever been documented, and no clutch count exists for it. Members of the flock are generally modest in fecundity, brooding on the order of a few dozen eggs and young — figures of roughly 20 to 80 are typical for haplochromines of this size — a small-clutch, high-investment strategy that trades fecundity for the protection mouthbrooding provides. The species has no known captive breeding history. The clutch figure given here is a genus-typical estimate, not a measurement for altigenis.
In the aquarium
Haplochromis altigenis is not an aquarium fish in any meaningful sense. It has effectively never been kept or bred in captivity, it is not in the hobby or the ornamental trade, and — being presumed extinct or at best vanishingly rare in the wild — it is almost certainly impossible to obtain. The genuine conservation aquaria and zoo programmes that maintain a handful of Lake Victoria haplochromines as living refugees work with a small number of surviving species, and this is not among them. Anything written about hypothetical husbandry would be invention. For context only: were such a fish available, it would be a large, actively predatory haplochromine needing a long tank, hard alkaline water in the mid-20s Celsius, and a diet built around whole fish and meaty foods, and it could not be housed with anything small enough to swallow. But the honest statement is the important one — Haplochromis altigenis belongs to the history and conservation literature of Lake Victoria, not to the aquarium.
Conservation
The IUCN Red List assesses Haplochromis altigenis as Data Deficient (assessed 31 March 2010 by Witte, F. and de Zeeuw, M.P.), with the population trend listed as unknown. The Data Deficient category reflects how little is known about the species' current status rather than any sign that it is secure: the assessment identifies predation by introduced Nile perch (Lates niloticus) as the main threat, compounded by hybridization risk where decreased water transparency disrupts the colour-based mate recognition that keeps species apart, and by general water-quality degradation. Eschmeyer's Catalog of Fishes is blunter, listing the species' status as extinct. Both readings sit within the same grim history: after Nile perch became established in Lake Victoria through the mid-20th century, and as eutrophication from a swelling human population turned the once-clear water turbid and oxygen-poor, an estimated 200 or more endemic haplochromine species disappeared or crashed in what is among the largest documented vertebrate extinction events of modern times. Whether a remnant of altigenis survives undetected in some refuge is unknown — that uncertainty is precisely why it remains formally Data Deficient rather than declared extinct — but it has not been reliably recorded for many years, and the weight of evidence is that it is gone or nearly so.