Taxonomy & naming
Aulonocara sp. "Deep Yellow" is a provisional, informal name for an undescribed peacock in the assemblage of offshore, deep-water sand-dwellers that Gunther Turner documented in his monograph on the offshore cichlids of Lake Malawi. These are not the reef peacocks of the aquarium trade but a distinct ecological guild of the open sandy bottom of the lake's south-east arm, collected mainly by trawling because they live away from rock and below diving depth. The name follows Malawi field convention — genus, "sp.", and a descriptive epithet in quotation marks — to mark that the taxon is not formally described. Its affinity is to the deep-water sand-dwelling Aulonocara grade of the open floor, stated honestly as an ecological and morphological grouping rather than a determination. With no published description there is no holotype, no fixed type locality, no authority, and no year; any FishBase number or IUCN status attached to this name elsewhere would be unfounded.
The epithet "Deep Yellow" — for the yellow nuptial cast and the deep open-sand habitat — is a hobby/field designation with no nomenclatural standing. It is not italicised in formal usage, takes no authority and no date, and would acquire neither unless a worker publishes a description fixing a type and diagnosis under the International Code of Zoological Nomenclature. Trawl-caught offshore Aulonocara have lagged behind the conspicuous reef peacocks in formal study because they are hard to collect and observe; Turner's offshore work brought many such forms to light under working names. "Deep Yellow" is one of these, grouped with the deep-water sand-dwelling Aulonocara of the south-east arm on habitat and general morphology — a provisional grouping. The responsible course, taken here, is to use the quoted informal name, withhold any invented author or year, and describe what is observed rather than assert a rank the form has not received.
Morphology
Aulonocara sp. "Deep Yellow" is a peacock of typical genus build — a moderately deep, laterally compressed haplochromine body — bearing the diagnostic head apparatus of the genus: lateral-line canals widened into a system of conspicuously enlarged sensory pores used to detect buried prey. Nuptial males show a yellow cast, soberer than the brilliant yellow-and-blue of the shallow reef peacocks but the basis of the form's name; females and non-territorial males are plainer and cryptically marked over silvery-brown, the usual peacock sexual dichromatism with males running larger. Precise meristic and morphometric figures are not available because no formal description has been published, so a fixed maximum length or fin-ray count should not be cited as established. What is reliable is qualitative: a sand-dwelling offshore peacock with the genus's enlarged cephalic pores and a yellow male nuptial colour.
Habitat
Aulonocara sp. "Deep Yellow" inhabits the open sandy floor of Lake Malawi's south-east arm, the broad southern basin that supports much of the lake's sand-dwelling cichlid community. It is an offshore form taken by trawl over featureless sediment rather than observed on rock; documented depths for the offshore sand-dwelling Aulonocara of this region run well down the water column, characteristically into the deeper trawled zone of roughly 66–197 ft, consistent with the "deep" in its name. The water is Lake Malawi's warm, hard, strongly alkaline medium: temperatures around 75–82 °F in the upper column (cooler at depth), pH in the alkaline 7.7–8.6 range, and high carbonate hardness. Because the name is informal and no field assessment has delimited its distribution, the locality given here marks the south-east-arm offshore sand habitat with which the form is associated in Turner's survey work, not a formally established range.
Feeding
Like all peacocks, Aulonocara sp. "Deep Yellow" is a sand-sifting micro-invertivore that locates prey through the ampullary and enlarged lateral-line pores of the head. Over the open offshore floor it hovers just above the sediment, holding station while the cephalic sensory system registers the faint movements of invertebrates buried below; on detecting prey it darts down, takes a mouthful of sand, sifts out edible items, and expels the spent grains through the gills and mouth. This benthic strategy suits the featureless soft bottom the form occupies, where prey is hidden in the sediment rather than associated with rock. Were it kept in captivity, the husbandry implication is the genus standard: a fine sand bed permitting natural sifting and a varied diet of fine prepared foods plus small live or frozen invertebrates such as chironomid larvae and brine shrimp.
Mating
As a Lake Malawi haplochromine, Aulonocara sp. "Deep Yellow" is expected to be polygynous and lek-like, with no pair bond — the social pattern shared across the peacock radiation. Males in nuptial colour establish and defend small territories on the open sand, each typically centred on an excavated pit or bower in the sediment, since the offshore habitat offers little rock; females are non-territorial and move across the floor visiting displaying males. Courtship is brief and conventional for the genus: a ripe female approaches a colour-flashing male at his sand territory and spawning follows. Sand-dwelling peacocks of the open floor are classic bower- or pit-spawners. Direct behavioural observation is limited because these are trawl-caught offshore fish, so the account here is drawn from the established pattern of the sand-dwelling Aulonocara grade.
Breeding
Aulonocara sp. "Deep Yellow" is, like every member of the genus, a maternal (ovophilous) mouthbrooder. After courtship draws a willing female to the male's sand territory, she lays a small batch of eggs and immediately takes them into her mouth; drawn to the egg-spot markings on the male's anal fin, she mouths at these and takes in milt that fertilises the clutch already held in her buccal cavity. Aulonocara clutches are modest — typically a few dozen eggs — and the female broods them in her mouth for roughly three to four weeks, feeding little or not at all, before releasing free-swimming fry; she then provides no further care, and there is no biparental investment. Deliberate captive breeding is uncommon because these trawl-caught offshore forms rarely enter aquaria, but the reproductive mode is the standard maternal mouthbrooding of the genus.
In the aquarium
Aulonocara sp. "Deep Yellow" is fundamentally a survey-documented offshore fish rather than an aquarium staple, and that should temper any husbandry discussion: it is taken by trawl from deep open sand, not collected for the trade in numbers. Where such fish are maintained at all, the principles follow the sand-dwelling peacock grade.
A single male with three or four females is the natural arrangement and avoids the aggression surplus males direct at rivals. Provide a large footprint — at least 47 in — with generous open swimming space and, for an open-sand species, a broad, deep, fine sand bed of at least 2 in that lets the fish dig a bower and display natural sifting and hovering. Rock is less important than for the reef peacocks and should not crowd out the open sand the fish needs. Dense planting is neither natural nor required.
Water chemistry should mirror Lake Malawi: temperature about 75–82 °F, pH 7.7–8.6, and moderate-to-hard general hardness, with soft or acidic water avoided. Weekly partial water changes of 20–30 % keep nitrate down. Diet is the standard peacock regime — a quality cichlid pellet or flake staple plus frozen or live chironomid larvae, brine shrimp and daphnia fed over the sand to encourage natural sifting — while high-fat foods, which predispose Malawi cichlids to bloat, are best avoided. Because the form is undescribed and rarely kept, any stock should be treated as of uncertain provenance and never crossed with reef peacocks; maintaining it as a clean, record-kept line is the responsible approach.
Conservation
No IUCN Red List assessment exists for Aulonocara sp. "Deep Yellow", and none can, because the form has not been formally described — the Red List evaluates validly named taxa. Its conservation standing is therefore unknown, and no status, category, or assessment year should be attributed to it. Contextually, the offshore sand-dwelling cichlid community of Lake Malawi's south-east arm is the part of the fauna most exposed to commercial trawl fishing, which is the principal documented pressure on the deep open-floor species rather than the ornamental trade that threatens conspicuous reef peacocks; whether "Deep Yellow" represents a distinct narrowly distributed form or a wider-ranging population caught up in that fishery cannot be resolved until its taxonomy is. The honest position is that this is an unevaluated, informally named, trawl-documented form whose identity is unsettled, and any claim about its conservation status should be regarded as unsupported.