Taxonomy & naming
Haplochromis elegans was described by the British ichthyologist Ethelwynn Trewavas in 1933, in her account of the cichlid fishes of Lakes Edward and George (Journal of the Linnean Society of London, Zoology, vol. 38). The original combination is Haplochromis elegans, and the name has remained valid ever since. The type series came from Lakes Edward and George and the Kazinga Channel; Eschmeyer's Catalog of Fishes records the lectotype as BMNH 1933.2.23.381 in the Natural History Museum, London, with a substantial set of paralectotypes, the lectotype having been designated by P. H. Greenwood in his 1973 review of the Lake George/Edward Haplochromis. Greenwood placed the species in his informal grouping near Haplochromis cinereus, and van Oijen and colleagues retained it as Haplochromis elegans in the 1991 CLOFFA check-list of African freshwater fishes. The genus Haplochromis is famously a holding pen for hundreds of East African haplochromine cichlids, and modern workers frequently move species of this grade into Astatotilapia; Haplochromis elegans is among those sometimes listed as Astatotilapia elegans. Because the wider taxonomy of the Lake Edward flock is still being worked out — recent revisions have, for example, expanded the lake's piscivores "from a pair to a dozen" — this atlas keeps the long-established Haplochromis heading while noting the Astatotilapia usage.
Morphology
This is a small cichlid: FishBase gives a maximum length of about 3 in (a male/unsexed figure that is effectively the size of a mature adult, not a giant). The body is the unremarkable, moderately deep, laterally compressed shape typical of generalist haplochromines — so much so that when Barel and co-workers set out in the mid-1970s to define a reference "generalised Haplochromis" morphology for measuring all the others against, they built it around Haplochromis elegans. In practice that means it has no single dramatic specialisation of jaw or body to point to; its proportions sit near the centre of the lake's morphological spread. Trewavas's original description noted clear sexual dichromatism in colour: breeding males are darker than females, with two dark bars across the snout, one below the eye and one on the preopercle, a dusky throat and belly, dark-edged or spotted dorsal and caudal fins, dark pelvics, and an anal fin bearing two or three ocelli — the yellow-orange "egg-spots" that are the signature of the haplochromine radiation and that play a role in mouthbrooding courtship. Females and non-breeding fish are plainer and paler. The epithet elegans ("fine, select, elegant") was not explained by Trewavas, but the bright, contrastingly marked nuptial male is the likeliest inspiration.
Habitat
Haplochromis elegans is endemic to the Lake Edward system in the Albertine (western) Rift — Lake Edward itself, the smaller and highly productive Lake George to its northeast, and the Kazinga Channel that joins them. The system straddles the equator (FishBase places the species between 0° and 1°S) on the border between Uganda and the Democratic Republic of the Congo, and falls within the Lake Victoria Basin freshwater ecoregion as mapped by FEOW. It is a benthopelagic, non-migratory inshore fish: it occurs especially near papyrus-fringed shores over sandy bottoms, the shallow, vegetated margins where its insect prey is abundant. Published in-situ chemistry specific to this species is thin, but the Edward/George waters are warm, well-mixed equatorial lakes that run alkaline — broadly pH on the order of 8 to 9 and surface temperatures in the mid-20s Celsius — and Lake George in particular is famously eutrophic and phytoplankton-rich. No depth range is recorded for the species in FishBase; as an inshore papyrus-and-sand fish it is a creature of the shallow littoral, on the order of the first metre or two of water, rather than the open lake. Field surveys of the system confirm this connectivity directly: most of Lake George's roughly sixteen Haplochromis species, H. elegans among them, also turn up in the Kazinga Channel and Lake Edward itself — the one clear exception being H. petronius, confined almost entirely to Kashaka Bay, an isolated extinct-volcano crater on Lake George. In the same survey work, H. elegans and the related H. limax were netted only in modest numbers compared with the more abundant stout-bodied Haplochromis of the open shallows, such as H. aeneocolor (Konings, Cichlids Yearbook Vol. 5).
Feeding
Haplochromis elegans is an insectivore. FishBase, drawing on Greenwood's work, reports that it feeds mostly on chironomid (non-biting midge) larvae, with emergent aquatic Diptera taken when available — in other words it works the sandy, papyrus-edged bottom for midge larvae and snaps at hatching adult midges at the surface as they emerge. Its estimated trophic level is about 3.2, consistent with a small invertebrate-feeder rather than a plant-scraper or a fish-eater. This benthic-insectivore guild is one of the recurring "trades" into which the Edward/George haplochromine flock has radiated, alongside algae-grazers, mollusc-crushers, zooplankton-pickers and the piscivores; Haplochromis elegans sits squarely in the insectivore lane, and its very generality of form is what made it a useful morphological baseline.
Mating
Direct behavioural observations of Haplochromis elegans in the wild are scarce, but its reproductive biology can be read confidently from its anatomy and from its many close relatives. Like the rest of the modern haplochromine radiation it is a polygynous maternal mouthbrooder, which means males do the displaying and females do the parental work. A ripe male takes on the dark nuptial dress Trewavas described and presents his anal-fin egg-spots to passing females. The egg-spots are the engine of the haplochromine courtship: after a female lays and immediately takes her eggs into her mouth, she snaps at the dummy "eggs" on the male's anal fin, drawing in his milt and fertilising the clutch she is already brooding. There is no lasting pair bond and no shared territory; the male's investment ends at fertilisation.
Breeding
FishBase records the mode plainly: "mouthbrooding by females." After spawning, the female carries the fertilised eggs and then the developing larvae in her buccal cavity, releasing free-swimming fry only once they are well developed and, for a time, taking them back into her mouth at any sign of danger. This maternal mouthbrooding sharply limits clutch size relative to substrate-spawning cichlids — the eggs are large and yolky and the brood is capped by what will fit in the mother's mouth. No clutch count has been published specifically for Haplochromis elegans; in small Astatotilapia-grade haplochromines of this size, broods are typically only a few tens of eggs (commonly on the order of 20–60), and that genus-typical figure is the best available guide here. The strategy needs no nest, no substrate and no second parent, which is part of why these little mouthbrooders proved so successful and so explosively diverse across the East African lakes.
In the aquarium
Haplochromis elegans is essentially not an aquarium fish. It is a small, plainly coloured, range-restricted insectivore from two African lakes that support no ornamental export trade comparable to Lakes Malawi or Tanganyika, and it does not appear in the hobby under its own name. There is no body of keeping experience to draw on and no commercial supply; the fish a hobbyist might encounter labelled "Lake Edward Haplochromis" are far more likely to be one of the lake's brighter relatives, or a misidentification. If one were ever maintained — most plausibly in a research or conservation-breeding context — the sensible starting point would be to mirror the wild environment: hard, alkaline water (pH roughly 8 to 9), warm temperatures in the mid-20s Celsius, a sandy bottom with shelter, and a varied small-invertebrate diet built around frozen or live chironomid larvae and other insect foods, with the understanding that the species is a maternal mouthbrooder and would brood in a quiet, well-structured tank. For the ordinary aquarist, this is a fish to read about rather than to keep.
Conservation
The IUCN Red List assesses Haplochromis elegans as Least Concern (assessed 31 January 2006 by T. K. Twongo; published 2006), with the population trend listed as Unknown and "no clear threats known" at the time of assessment. The species is recorded from Uganda and the Democratic Republic of the Congo, the two countries that share the Lake Edward system. It carries no CITES or CMS listing. That reassuring category should be read against the backdrop of the Edward/George basin as a whole, which faces real and growing pressure: rapid human population growth around the lakes, heavy and in places overexploited artisanal fisheries, nutrient loading, and habitat disturbance in the very inshore, papyrus-fringed margins this species depends on. The Lake Edward haplochromine flock has historically been understudied — basic taxonomy is still being revised and new species are still being described — so abundance trends for any single small insectivore like Haplochromis elegans are poorly resolved. The 2006 assessment predates much of that recent work and would benefit from a modern reassessment, but on present evidence the species is widespread within its system and not considered threatened.