Taxonomy & naming
Aulonocara ethelwynnae was described in 1987 by the German workers Manfred K. Meyer, Rüdiger (Rolf) Riehl and Horst Zetzsche, in a revision of the genus Aulonocara published in volume 94 of the Courier Forschungsinstitut Senckenberg (pages 7–53) that erected six new species at once. Eschmeyer's Catalog of Fishes records the holotype as SMF 21145, with a series of twelve paratypes catalogued as SMF 21146, all held in the Senckenberg Museum in Frankfurt; the type locality is given as Chitande (spelled Chitendi in some sources) Island, Lake Malawi — the Malawian portion of the lake the older literature still calls Lake Nyasa. The genus Aulonocara Regan, 1922 gathers Lake Malawi's "peacock" cichlids, a tight group of sand- and intermediate-zone haplochromines diagnosed by the conspicuously enlarged lateral-line canals and sensory pores that open across the head and lower jaw. Within that radiation, Ad Konings and the Cichlid Room Companion place Aulonocara ethelwynnae among the so-called "Chitande Types" — a knot of small, deeper-living northern peacocks that are notoriously difficult to tell apart. One caveat runs through every careful account of this fish: malawi.si (the M.K. Oliver / Stuart Grant database) notes that Aulonocara ethelwynnae effectively "lacks a formal diagnostic description," so its boundary against undescribed siblings such as Aulonocara sp. 'chitande type north' rests on a handful of colour and body-shape characters rather than a rigorous morphological diagnosis. Against its one described chitande-group neighbour, Aulonocara auditor — the two are sympatric only at Ngara and Mdoka, the sole sites where two chitande-type species share the same reef — Konings found the separation more straightforward: A. auditor carries a distinctly longer, straight-profiled snout, against the rounded snout of ethelwynnae and every other chitande-type species. There are no synonyms. FishBase auto-applies the labels "Chitande aulonocara," "Chisawasawa" and "Northern aulonocara," but none of these is an established hobby or trade name — in practice the fish is sold and discussed by its scientific name or, loosely and often misleadingly, lumped with the other "chitande" peacocks — so no English common name is asserted here.
Morphology
This is one of the smallest peacocks. FishBase, drawing on the CLOFFA checklist, lists a maximum of just 3 in standard length, while field and hobby references following Konings give a larger live size — mature males to about 4.5 in and females to roughly 3.5 in total length — the usual peacock pattern of males running larger, and the discrepancy partly reflecting SL versus TL and museum versus aquarium fish. The body is the moderately deep, laterally compressed haplochromine form, and the head carries the genus's signature: a system of enlarged cephalic sensory pores, the facial lateral-line canals widened into pits that register the movements of prey hidden in the sand. Sexual dichromatism is clear. Dominant, territorial males take on a yellow cast over the flanks, with the dorsal, anal and caudal fins flushing metallic blue under good light; females and non-breeding males are a plain, often rather dark brown-grey. Both sexes carry egg-spots (ocelli) on the anal fin, though males tend to bear more of them and in a brighter yellow. Two characters do most of the work of separating Aulonocara ethelwynnae from its undescribed northern relatives, per malawi.si: females and non-breeding males show distinct black lappets (the small flaps between the dorsal-fin spines), and the body is comparatively deep. Critically, breeding males lack the white-to-blue submarginal band along the dorsal fin that marks the similar Aulonocara sp. 'chitande type north' — a small but reliable field mark in a complex where the drab females are essentially impossible to tell apart.
Habitat
Aulonocara ethelwynnae is a Lake Malawi endemic restricted to the lake's far northwestern shore. FishBase, taking the conservative view, calls it endemic to Chitande Island alone; the fuller picture from malawi.si and Konings is a narrow coastal strip running from the Ngara area southwards to Chilumba, with a strong population at Chitande Island and only occasional records from Mdoka — the single other site where it is sometimes encountered. Its biotope is the classic Aulonocara "intermediate" zone: open sand interrupted by scattered rocks and small rubble heaps, rather than continuous rock or clean sand. The species is unusual among peacocks for how deep it lives. Territorial, breeding males hold sites at roughly 49–82 ft, below the depth at which most congeners set up; foraging females and immature, non-breeding males form loose shoals much shallower, as little as about 10 ft down, and only descend to the males' territories to spawn. The water is the warm, hard, alkaline medium of Malawi's upper layers — FishBase gives an in-situ range of about 72–79 °F and pH 7.4–8.0 — and the northwestern reefs are characteristically low in clarity for much of the year, a turbidity that suits a fish hunting by vibration rather than sight.
Feeding
Like all peacocks, Aulonocara ethelwynnae is a sand-sifting invertivore, and its enlarged head pores are the tool of the trade. Hovering just above the sand, the fish listens through those cephalic canals for the faint stirrings of buried prey, then darts down and takes a mouthful of substrate, sifting out edible items — chiefly small crustaceans and insect larvae — and expelling the spent sand through the gills and mouth. FishBase records the diet simply as bottom-dwelling invertebrates and places the species at a trophic level of about 3.5, squarely a benthic micro-predator rather than an algae grazer. Where it shares a reef with the sympatric Aulonocara auditor, at Ngara and Mdoka, Konings suggested the two may partition the sand vertically rather than compete directly: A. auditor's longer, straight snout may let it probe deeper into the substrate than ethelwynnae can manage, reaching a different population of buried invertebrates — though he also judged food likely abundant enough there that the two species are not meaningfully competing regardless. In the community of the northwestern reefs it occupies the soft-sediment foraging niche between and around the scattered rocks, a role that ties it to clean, invertebrate-rich sand. In captivity that translates to a fine sand bed (coarse gravel both blocks the sifting behaviour and risks abrading the gills) and small live or frozen invertebrate foods — though keepers caution against fatty staples such as tubifex and red mosquito larvae, which sit poorly with Malawi cichlids; finely crushed flake and small frozen items are taken readily.
Mating
Aulonocara ethelwynnae is polygynous and lek-like in its social organization, with no pair bond — the standard Malawi-haplochromine arrangement. Males in nuptial colour hold and defend small territories, each centred on a cave or excavated pit among the scattered rocks of the reef; tellingly, those territories sit at the deeper levels, around and below 49 ft, and the males are coloured and territorial year-round rather than only in a brief breeding season. Aggression is low for an African cichlid and is directed largely at rival conspecific males; the fish does not contest space with the wider community the way the rock-dwelling mbuna do. Females and non-breeding males range more widely and shallower, and a ripe female descends to visit a displaying male at his site. Courtship is conventional for the genus: the male intensifies his colour, spreads his fins to present his flank broadside, and quivers his body to lead the female down to the spawning spot. It is a quiet, deep-water lek rather than the crowded, brawling arena of the shallow rocky shore.
Breeding
Aulonocara ethelwynnae is a maternal (ovophilous) mouthbrooder. Spawning usually takes place inside the male's cave, but the fish will also spawn on open sand when no suitable cave is available. The pair circle one another over the site; the female lays a small batch of eggs and immediately takes them into her mouth, then is drawn to the egg-spot markings on the male's anal fin and, in trying to gather these false "eggs," takes in milt that fertilizes the clutch already held in her buccal cavity — the classic egg-spot mechanism of the haplochromines. Clutches are small, in keeping with the fish's modest size. The female broods alone, the eggs hatching within her mouth after a few days and the free-swimming fry remaining sheltered there for up to about three weeks before she releases them to fend for themselves; there is no male or post-release parental care. Newly released fry take freshly hatched brine shrimp and finely powdered foods. In the aquarium the species breeds without special intervention given a settled harem, and keepers who want to raise a brood typically strip or isolate the holding female toward the end of the brooding period, since released fry are quickly eaten in a community tank.
In the aquarium
Aulonocara ethelwynnae is an uncommon fish in the trade. It is occasionally available from specialist cichlid importers and breeders who work with the northern-Malawi peacocks, but hobbyists are far more likely to encounter the commoner and larger ornamental Aulonocara species — the yellow and OB peacock morphs that dominate the mass market — so anyone specifically seeking Aulonocara ethelwynnae should expect to search and to pay a specialist price. Even among peacock keepers it is considered a more subdued fish than the heavily domesticated show forms, which suits those looking for the closer-to-wild experience that the chitande types represent.
A tank of at least 40–50 US gal suits a harem of one male with two or three females and gives the most comfortable margin; given the species' small adult size — males to around 4.5 in total length, females somewhat smaller — a larger footprint is more important than raw volume, so a tank measuring at least 39.5 in long is a reasonable floor. Konings' own stocking notes (Enjoying Cichlids) list a 100-litre tank as workable for exactly that ratio — one male, three females — which underlines how modest this species' real footprint requirement is compared with the larger show peacocks; a keeper genuinely tight on space is not badly served by the smaller figure, though more room is always better. Lake Malawi chemistry is essential: hard, alkaline water at pH 7.8–8.2 (the lake's in-situ range runs to about 8.0; aquarium water drifting up to 8.5–8.6 is acceptable and commonplace with a coral-sand or crushed-coral substrate), carbonate hardness of 10–20 dKH, total hardness in a similar range, and temperature held between 75–79 °F. Soft or acidic water will suppress colour and health over time and should not be considered a workable compromise.
The biotope principle matters practically here, not just aesthetically. A fine-sand substrate — pool-grade silica sand or a comparable medium-grain option — is non-negotiable for this sand-sifting invertivore; coarse gravel or bare glass prevents the foraging behaviour and can damage the gill filaments when the fish takes mouthfuls of substrate. Build rockwork around the periphery and back, leaving open sand in the foreground where the male can establish and patrol his territory. Stacked rocks with caves or overhangs approximate the natural site; the fish does not need elaborate structure but does benefit from at least one defensible retreat per male territory. Moderate, steady filtration is preferable to turbulent flow; this is not a river fish.
Companion choice is the most consequential husbandry decision. The chitande-type peacocks are quiet fish and are quickly overwhelmed by aggressive tankmates. Mbuna — the rock-dwelling haplochromines that dominate many mixed Malawi tanks — are generally unsuitable partners for Aulonocara ethelwynnae: even modestly territorial mbuna species will outcompete the peacock for food, harass females off condition, and bully the male into fading. If mixing is attempted, choose only the gentlest mbuna species and provide enough visual separation that the peacock can hold a corner of the tank as its own. The more tractable pairing is with other peacocks or with the deeper-water Malawi haplochromines (Copadichromis, Placidochromis), provided the ratio of males to females is managed carefully. One male Aulonocara ethelwynnae per group is the rule — two males in anything short of a very large tank means chronic aggression. The gravest long-term risk in any Aulonocara community is hybridisation, but the rule of thumb is narrower than "one Aulonocara per tank." Konings' own guidance (Enjoying Cichlids) is that the risk sits within a group of closely related geographical races, not across the genus as a whole: he lists Aulonocara jacobfreibergi, ethelwynnae, stuartgranti, and guentheri as species that can be housed together in one community without meaningful hybridisation risk, because each represents a visually and behaviourally distinct lineage. The practical rule that does hold for ethelwynnae is the one within its own group — given how similar the chitande types are to one another, mixing Aulonocara ethelwynnae with any other chitande race or the closely related, undescribed northern siblings guarantees hybrid fry, and only one such race should be kept per tank.
Diet and breeding are straightforward by Malawi standards. High-quality small cichlid pellets, crushed Spirulina flake, and small live or frozen invertebrates — brine shrimp, daphnia, mysis, cyclops — keep condition and colour good; avoid fatty red-mosquito larvae and tubifex, which are consistently implicated in the bloat and intestinal problems that affect Malawi cichlids. Breeding requires only a settled harem and stable water: the female broods for roughly three weeks and should be isolated — or gently stripped near the end of the brood period — before release, as fry are taken immediately in a community tank. Difficulty is moderate for someone already keeping Malawi cichlids; it is above average for a newcomer to the rift-lake group who lacks the water-chemistry infrastructure.
Conservation
The IUCN Red List assesses Aulonocara ethelwynnae as Near Threatened, assessed on 23 May 2018 by Ad Konings under criteria B1a+2a — a status that turns on its very small range. The fish is genuinely common at Chitande Island but only sporadically present at Mdoka and effectively absent elsewhere, so its extent of occurrence and area of occupancy are tiny, and a population concentrated on a single reef is inherently vulnerable to local disturbance. It is exported for the aquarium trade, though it is a niche fish rather than a heavily collected one, and it carries no CITES listing. The narrow-endemic peacocks of the northwestern coast sit within a basin under broad and worsening strain: Lake Malawi faces shoreline development and the sedimentation that follows catchment deforestation — a direct threat to a sand-and-rock fish that depends on clean substrate and clear-enough water to forage — alongside warming surface waters and reduced deep mixing that lower the productivity supporting the lake's fishes, and heavy artisanal and commercial fishing pressure across the basin. None of these is documented as an immediate, species-specific danger to Aulonocara ethelwynnae, whose chief vulnerability remains its restricted distribution, but they are the backdrop against which a single-reef endemic's long-term prospects must be read.