Taxonomy & naming
Aulonocara steveni was described by Manfred K. Meyer, Rüdiger Riehl and Hermann Zetzsche in 1987, in their revision of the genus Aulonocara published in Courier Forschungsinstitut Senckenberg (volume 94, pages 7–53). The type locality is Kande Island, off the northwestern shore of Lake Malawi; the holotype (SMF 21151) and paratypes (SMF 21152) are held at the Senckenberg Museum in Frankfurt. The genus name joins the Greek aulos (a flute or pipe) with kara (head), a reference to the conspicuous open sensory canals and pores that channel the heads of these fishes. The epithet honors Steven Longwe, a fisherman at Salima, Malawi, who collaborated with the authors and supplied them with specimens — the original description says nothing more about him.
The name sits at the center of a genuine, unresolved disagreement. FishBase and the GBIF taxonomic backbone both still list Aulonocara steveni as a valid species. Eschmeyer's Catalog of Fishes, however, following Ad Konings's 2016 treatment in Malawi Cichlids in their Natural Habitat, now regards steveni — together with Aulonocara hansbaenschi — as a junior synonym of the older Aulonocara stuartgranti Meyer & Riehl, 1985. The IUCN Red List takes the same view, assessing all three names as a single species. The disagreement is biological as much as nomenclatural: the sand-dwelling Aulonocara of Malawi are a tight, very recently radiated cluster of geographically variable forms, and where one worker sees distinct species another sees colour morphs of one widespread fish.
The hobby muddle is worth untangling directly, because the popular literature gets it backwards as often as not. In the trade, the name "steveni" attaches most firmly to the "Usisya" peacock — the original yellow-bodied, dark-finned flavescent fish from the northwestern coast. The famous orange-tailed "Ngara flametail" and the blue "Usisya"/"Cobue"/"Blue Neon" morphs that hobbyists also call peacocks are catalogued under stuartgranti, and aquarists routinely (and incorrectly) lump or swap the labels. Provisional trade names tied to this complex — "flavescent peacock," "Usisya," "Blue Dorsal," the umbrella label "Aulonocara nyassae" — are sales descriptors for collecting localities, not established English names for a biological species, which is why this article assigns no common name.
Morphology
This is a small-to-moderate peacock. FishBase records a maximum of 3.5 in standard length for the type series (after Maréchal 1991), while field and aquarium reports for the broader steveni/stuartgranti complex run larger — roughly 4.5 in for females and up to about 5.5 in total length for well-grown territorial males. As with most peacocks, the published "maximum" depends heavily on whether the figure is a wild standard-length measurement or a tank-grown total length, so the smaller museum number and the larger hobby number are not really in conflict.
The sexes are strikingly different. Dominant males carry a metallic blue head and gill covers over yellowish-blue flanks crossed by eight or nine dark vertical bars; the intensity of the yellow varies from population to population. The dorsal fin may be blue or more or less yellow-tinged but is consistently edged in white to whitish-blue, and in some populations it also bears a dark longitudinal stripe — a feature that helps separate steveni-type fish from the closely related Aulonocara baenschi (which lacks the blue, black-pigmented dorsal) and from typical stuartgranti (distinguished by the yellow flank wash). The anal fin is variably dark and carries egg-spots (ocelli) in differing numbers. Females and subordinate or stressed males of every population are far more uniform: silvery-grey to brown, with the dark vertical barring showing more clearly than in nuptial males. Because full male colour appears only once a fish holds a territory, drab juveniles and non-dominant males are a recurring source of identification confusion.
Habitat
Aulonocara steveni is endemic to Lake Malawi. FishBase localizes the type population to the vicinity of Kande Island on the northwestern shore (roughly 11–13°S); under the broader stuartgranti circumscription the IUCN traces the species along the western shore from Ngara south to Kande Island, along the eastern (Tanzanian) shore south of the Ruhuhu River, and down the entire Mozambican coast to Chimwalani Reef. The northwestern "Usisya" populations most associated with the steveni name occupy the stretch of coast between Ngara and Kande Island.
Ecologically it belongs to the lake's "intermediate" zone — the transitional biotope where rocky reef gives way to open sand, rather than the pure rock of the mbuna or the deep open sandflats of fishes like Aulonocara rostratum. It is typically found in shallow water down to a maximum of about 66 ft, among sediment-covered rocks and over mixed rock-and-sand bottoms. Males hold small territories beneath and between rocks, favouring large overhanging boulders that suspend over sand, while females and non-breeding males forage out on the adjacent sediment and bolt for cover among the rocks when disturbed; some subpopulations are shy cave-dwellers, others form open schools over the sand. The water it lives in is the characteristic Malawi envelope of the upper water column: warm (roughly 75–82 °F), hard, alkaline (pH near 7.7–8.6) and well oxygenated.
Feeding
Like all peacocks, Aulonocara steveni is a sand-sifting micro-carnivore, and FishBase places it at a trophic level of about 3.5 — squarely a predator on small benthic prey rather than an algae grazer. In the lake it hovers a short distance above the bottom and strikes down at soft-bodied invertebrates — small crustaceans, snails and insect larvae — that it extracts from the sand and from the sediment film coating the rocks. The genus's hallmark is how it locates prey it cannot see: the enlarged cephalic lateral-line canals along the lower jaw detect the faint water movements of buried invertebrates, a sixth-sense feeding system that has been demonstrated directly in the related Aulonocara stuartgranti and that explains both the fish's hovering hunting posture and the sensory pits that gave Aulonocara its name. In the community it is one of many sand-foraging invertivores partitioning the intermediate zone's prey by microhabitat and depth.
Mating
Socially the fish follows the standard Malawi peacock template: it is polygynous, with dominant males defending small territories among the rocks while females and subadult males gather in loose groups over the surrounding sand. Each male's territory is centred on a sheltered spot — beneath or between rocks, often under a large overhang suspended over sand — within which he clears a small spawning depression in the sediment. A receptive female leaving the school is courted and led to this site. By Malawi-cichlid standards the species is mild: keepers and field workers describe it as peaceful and non-aggressive, a fish that cannot compete with boisterous mbuna and is best kept only with similarly calm tankmates, though territorial males will still spar with one another and pester females. Large cave systems can hold several territorial males at once.
Breeding
Reproduction is maternal mouthbrooding, the haplochromine norm. Spawning takes place at the male's territory, typically inside or beneath a cave or in the cleared depression at its centre: the female lays a small clutch, immediately takes the eggs into her mouth, and fertilizes them by mouthing the male's anal-fin egg-spots in the classic haplochromine fashion. She then broods the developing young in her buccal cavity for roughly three weeks, eating little, before releasing free-swimming fry. Wild clutches are modest and scale with female size — peacock broods generally run from a handful to a few dozen eggs — and well-conditioned females can spawn on a roughly monthly cycle. Detailed wild breeding observations specific to the steveni population are thin in the literature; the account above is the well-documented pattern for the stuartgranti complex to which it belongs, and captive breeders report the same behaviour, with a generous cool water change among the commonly cited (if anecdotal) spawning triggers.
In the aquarium
Aulonocara steveni — sold under names like "Usisya peacock," "flavescent peacock," or simply as a stuartgranti-complex location form — is a manageable Lake Malawi cichlid for a keeper who has already moved past community tropicals and is prepared to run a dedicated Malawi tank. It is not a beginner fish, but it is notably calmer than the mbuna it shares a lake with, and provided the setup respects its foraging biology and social requirements it is one of the more rewarding peacocks to keep. The main obstacles are water chemistry discipline, space for the harem structure, and the very real hybridization risk if tankmates are chosen carelessly.
Tank size and layout should reflect the fish's natural habitat at the rock-sand interface. A single male with a small harem can be managed in a tank of around 50 US gal (roughly 47 in long), but 65–95 US gal gives more working room, dilutes female harassment from the male, and allows a proper scape. The rear half of the tank should carry substantial rockwork — stacked to create caves, overhangs and visual breaks — while the foreground must be kept open with a deep bed of fine, light-coloured sand (at minimum 2–3 in). The sand is not merely cosmetic: like all peacocks, steveni-type fish hunt by hovering and plunging down onto the substrate, and a thin gravel layer or bare bottom forces the fish to abandon the foraging behaviour that defines it. Coarse substrate can also cause gill damage when sand is taken in during feeding strikes. Strong filtration is essential; Lake Malawi is effectively a soft-coral sea in miniature, and high organic loads push down pH and compromise the fish. Aim for pH 7.8–8.4, total hardness above 10 °dH, and temperature in the 75–81 °F range — all consistent with the lake values in the water data above.
The social unit in the aquarium mirrors the wild one: one dominant male to three or more females is the minimum harem ratio, and it is the single most common mistake keepers make to run a pair. With only one female, the male's courtship harassment is concentrated relentlessly on her; she may stop eating, lose colour, and eventually die. Three or four females distribute that pressure, and the male's territorial display is directed at defending his spawning site rather than tormenting a single fish. A second male in the same tank will result in either sustained fighting or a permanently suppressed subordinate; experienced keepers sometimes run two males only in very large tanks with rock structures that create genuine visual barriers.
Tankmate selection is where the steveni/stuartgranti complex requires the most care, for two distinct reasons. The first is behavioural: Aulonocara are among the gentler Malawi cichlids, and they fare poorly with mbuna (rock-dwellers in the genera Metriaclima, Pseudotropheus, Labeotropheus and relatives), whose sustained aggression and density of occupation in the rockwork will either shred the peacocks' fins or prevent them from foraging freely. Suitable companions are other peaceful haplochromines — large Copadichromis species, Placidochromis, Nyassachromis, or similarly calm utaka — and non-cichlid dithers like Synodontis catfish. The second reason is genetic: Aulonocara are interfertile across the genus, and males of different peacock species — or different location forms of the same species — will hybridize freely when housed together. The stuartgranti/steveni complex is particularly problematic because the trade's various "Usisya," "Ngara," "Cobue," and "Blue Neon" forms are often mixed on dealers' benches, and hybrids grow up to colour and are passed on, polluting the captive lines. Keeping a single Aulonocara species (and ideally a single location form) per tank is the only way to protect strain integrity.
Breeding in a well-set-up tank is straightforward and happens without much intervention. Males display intensively once established, spawning typically occurs in the cave or in the sand depression the male has cleared at its entrance, and the female will be visibly mouthbrooding (distended lower jaw, reluctance to eat) within days of a successful spawn. The incubation period is roughly three weeks at normal tank temperatures; some keepers move the brooding female to a separate vessel to strip and tumble the eggs artificially, which maximises yield, but the female will hold and release free-swimming fry on her own if left undisturbed in a tank where fry predation is low. Fry are large enough to take crushed flake and micro-pellets immediately on release. Cool, large water changes are often cited in the hobby literature as a spawning trigger for peacocks generally; this is plausible given seasonal lake dynamics, though controlled evidence is thin. The species is generally rated as moderately straightforward for a cichlid keeper with Malawi experience.
Conservation
There is no separate IUCN Red List assessment under the name Aulonocara steveni — FishBase explicitly lists it as Not Evaluated, because the Red List folds steveni into Aulonocara stuartgranti. That senior name was assessed as Least Concern by Ad Konings (assessed 22 June 2018, reviewer J. Snoeks), on the grounds that the species is endemic to Lake Malawi but very widely distributed, common at almost all localities, and — because it favours rocky areas — only rarely taken by subsistence seine fishermen; the assessment also concluded that ornamental-trade collection has had no measurable impact on wild populations. It carries no CITES listing. As a trade footnote, fish from Cobwé in Mozambique were translocated to Thumbi West Island inside Lake Malawi National Park.
Two honest caveats belong here. First, "Least Concern" attaches to the broad, lumped species; if the narrow-range "Usisya"/steveni form were treated as a distinct species, its much smaller distribution would warrant a fresh look, and at least one recent identification review has questioned whether the blanket Least Concern listing is appropriate for these locality-restricted Aulonocara. Second, a species-level pass does not mean the lake is healthy. Lake Malawi's nearshore habitats are under mounting strain from over-fishing, and from heavy sediment and nutrient loading washing off deforested catchments — and silt smothering the rock-sand interface degrades precisely the foraging and spawning habitat an intermediate-zone peacock depends on, while clouding the water blunts the visual half of its day-night feeding. The fish is not in trouble today, but its security rests on a lake whose shallow margins are quietly being eroded.