Taxonomy & naming
Aulonocara maylandi was described by the British ichthyologist Ethelwynn Trewavas in 1984, in the journal Revue française d'Aquariologie et Herpétologie (vol. 11, no. 1, p. 8, figs. 1-3). The holotype (BMNH 1984.3.27.1) and a series of paratypes are held in the Natural History Museum, London, and the type locality is Eccles Reef, near Makanjila Point on the eastern shore of Lake Malawi. The species was named for Hans-Joachim Mayland, the German aquarist, photographer and author who first brought the fish to Trewavas's attention. The genus Aulonocara — Regan's 1922 'peacock' group of sand-dwelling Malawi haplochromines — is diagnosed by its conspicuously widened cephalic sensory canals, a feature central to how these fish feed. The most contested point in the species' taxonomy concerns the Kande Island population. In 1987 Patrick Tawil and Robert Allgayer described it (in Cybium 11(2): 159-166, holotype MNHN 1986-0335) as a distinct subspecies, Aulonocara maylandi kandeensis, separated from the nominate form chiefly by a white-to-pale-blue dorsal blaze in place of the yellow one. Treatments since have diverged: Eccles & Trewavas (1989) regarded the differences as too slight to maintain and sank kandeensis into maylandi, whereas Ad Konings and several catalogues instead elevated the Kande fish to full species rank as Aulonocara kandeense. The Catalog of Fishes today lists both Aulonocara maylandi Trewavas, 1984 and Aulonocara kandeense Tawil & Allgayer, 1987 as valid, so the two are now generally handled as separate, allopatric species rather than as nominate-plus-subspecies. This article treats Aulonocara maylandi in the narrow sense — the yellow-blazed sulphurhead of Eccles and West Reefs — and flags the Kande fish where the older 'maylandi kandeensis' usage still appears in the trade and literature.
Morphology
This is a small peacock, with reported maximum sizes that vary by how length is measured: FishBase lists about 6 in total length, while hobby sources commonly cite roughly 4–4.5 in for males and somewhat less for females, and the original material was in the 3–4 in standard-length range. The body is the typical Aulonocara shape — moderately elongate, laterally compressed, with a gently sloping head and the enlarged, pitted cephalic pores along the lower jaw and snout that mark the genus. Coloration is strongly sex-linked. Dominant, breeding males are the spectacle: a dark, often blackish to blue-grey body overlain with faint vertical bars, and a vivid sulphur-yellow band that begins at the tip of the snout and runs back over the forehead, nape and dorsal body line — Ad Konings (Cichlids Yearbook), comparing it directly to the coloration of a ripening male Copadichromis, describes the band as continuing along the top of the back essentially to the base of the tail, rather than stopping at the leading edge of the dorsal fin. Fins may carry blue and yellow tones and the usual peacock egg-spots on the anal fin. Females and non-territorial males are far plainer: silvery-grey to brownish and cryptically barred, an inconspicuous camouflage suited to foraging out over open sand. Sexual dimorphism is therefore pronounced in colour and somewhat in size, with males larger and brighter; juveniles resemble females. The closely related Kande Island fish (kandeense) shares the body pattern but substitutes a white-to-pale-blue blaze for the yellow, which is the readiest field distinction between the two.
Habitat
Aulonocara maylandi is endemic to Lake Malawi and, in the strict sense, extraordinarily localized: it is reliably known only from Eccles Reef (Chimwalani Reef), the type locality near Makanjila Point, and from West Reef (Luwala Reef), both deep, isolated offshore reefs in the south-eastern arm of the lake. These are not fringing shore reefs but submerged rocky knolls rising from sand. The fish occupies the 'intermediate zone' where large boulders and rocky outcrops give way to open sand — the characteristic peacock biotope — at moderate depth, with field reports placing it broadly in the 33–66 ft range over and around the reef. Males hold territories at the rock-sand interface while females and immatures forage in loose groups out over the sand flats. As a Malawi rift-lake species it lives in hard, alkaline water: the lake runs to a pH of roughly 7.7-8.6, conductivity around 210-260 µS/cm, and surface temperatures generally about 75–82 °F, with the well-oxygenated habitable zone confined to the upper water column above the permanent oxycline. The extreme rarity of the fish — confined to two small reefs separated by deep open water it will not cross — is the single most important fact about its distribution and underpins its conservation status.
Feeding
Like other peacocks, Aulonocara maylandi is a benthic micro-invertivore that hunts by a sensory trick rather than by sight alone. It cruises just above open sand, then stops and hovers nearly motionless with its head angled down toward the bottom. The greatly enlarged canals of its cephalic lateral-line system — the 'flute-holes' that name the genus — detect the minute hydrodynamic disturbances made by small animals buried or moving in the substrate; the fish then lunges and takes a mouthful of sand, sifting out the prey and expelling the grit through the gills and mouth. Experimental work on the related Aulonocara stuartgranti has shown these widened canals let peacocks locate and capture buried invertebrate prey even in complete darkness, the first clear demonstration of non-visual, lateral-line-guided feeding in an African cichlid — a mechanism that applies directly to maylandi's foraging. The diet is accordingly dominated by small sand-dwelling invertebrates: insect (chironomid) larvae, micro-crustaceans such as ostracods, and other meiofauna of the sandy intermediate zone. In the community it is one of many specialized sand-sifters partitioning this prey field, set apart less by what it eats than by the reefs it is confined to.
Mating
Aulonocara maylandi is a polygynous, lek-influenced mouthbrooder with the social structure typical of the genus. Outside of breeding the sexes mix in foraging aggregations over sand, but as males mature and come into condition they take on the sulphur blaze and establish territories at the rock-sand boundary, often centred on a boulder, crevice or other landmark. A territorial male displays his yellow head and flank colour to females passing over his patch of sand, quivering and leading them toward his chosen spawning site. Rival males are driven off, and the brightest, best-situated males secure the most matings. Because fertilization and brood care happen in the female's mouth, the male's territory functions purely as a courtship and spawning arena rather than a nursery — there is no biparental defence of eggs or fry. This combination of male display colour, site-holding and female choice is the standard peacock pattern, and in aquaria the species behaves accordingly: relatively peaceful for a Malawi cichlid but with males that can be persistently aggressive toward each other and toward similarly coloured rivals.
Breeding
Reproduction follows the maternal-mouthbrooding mode universal to Aulonocara. After courtship the female lays a small clutch on the substrate within the male's territory and immediately takes the eggs into her mouth; she then mouths at the egg-spots on the male's anal fin, prompting him to release sperm that fertilizes the clutch inside her buccal cavity. Clutches are small — on the order of a few dozen eggs, in keeping with the species' modest size — and the female alone broods them, incubating the developing eggs and then the larvae in her mouth for roughly three weeks before releasing free-swimming fry. During this period she does not feed, and for a time after release she may continue to take the fry back into her mouth when threatened. The male provides no parental care. Wild spawning has not been documented in detail for this rare species specifically, but it breeds readily in captivity along exactly these lines, which is precisely why it became established in the trade despite its tiny natural range. The relatively low fecundity, late maturity and confinement to two reefs make the wild population slow to recover from over-harvest.
In the aquarium
Aulonocara maylandi is a moderately demanding peacock that rewards a keeper willing to match its natural conditions closely. A single-male group — one male to three or more females is the standard peacock harem ratio — needs a footprint of at least 59 in to allow the male a territory at one end while females have open water to retreat into. The tank floor should be a layer of fine, pale sand several centimetres deep, mimicking the intermediate-zone substrate on which wild fish spend most of their time. Rocky architecture along one or two walls — piled limestone or sandstone, with crevices and overhangs at the rock-sand boundary — provides the territorial focal points males instinctively seek; leaving the centre and front of the tank open sand gives the fish room to display and the keeper a clear view. Heavy planting is neither natural nor necessary, though a few robust background plants do no harm.
Water chemistry must mirror Lake Malawi: pH 7.8–8.6, hardness in the hard-to-very-hard range (roughly 10–25 °dH general hardness, with elevated carbonate hardness to buffer the pH), and temperature 75–82 °F. Crushed coral or aragonite substrate or a bag of coral rubble in the sump will help maintain hardness and buffer pH upward from soft tap water. Stable chemistry matters more than hitting any one value precisely; swings in pH are more stressful than a reading slightly outside the target window. Powerful filtration and a regular water-change schedule — 25–30% weekly is a sound baseline — keep nitrate low, which is particularly important for the female's health during the weeks she broods without eating.
Tankmates for Aulonocara maylandi should be chosen carefully. Other Aulonocara species of similar temperament, peaceful utaka (Copadichromis), and smaller, non-aggressive Malawi haplochromines are workable companions, provided the tank is large enough that territories do not overlap destructively. The critical risk with peacocks in mixed tanks is hybridisation: Aulonocara males will readily cross with females of other peacock species, and because most of the hybrids are attractively coloured, they circulate freely in the trade under invented names. Keepers who want to preserve Aulonocara maylandi as the species it is — a legitimate priority given its Critically Endangered status — should house it as a species group or with tankmates that are clearly not Aulonocara. Mixing it with rough mbuna is generally inadvisable; even relatively placid mbuna species can outcompete peacocks for food, harass females, and strip the breeding male of condition.
Feeding in captivity is uncomplicated: Aulonocara maylandi accepts high-quality cichlid pellets, frozen or live chironomid (bloodworm), daphnia, cyclops, and similar invertebrate-based foods readily. As a sand-sifter it is not a fast, open-water feeder, so a little patience at feeding time helps; sinking pellets or wet-frozen foods that reach the sand before the faster fish eat them play to the species' foraging style. Vegetable-heavy or high-fat mammalian-protein-based foods — beef heart in particular — are associated with internal bacterial disease ('Malawi bloat') in Lake Malawi cichlids generally and are best avoided entirely.
Breeding in captivity follows the same maternal mouthbrooding pattern described for the wild fish and happens without special intervention once adults are in condition. A gravid female will be noticeably fuller in the throat and jaw, and will stop feeding; she should not be disturbed or chased during the roughly three-week hold. Removing her to a quiet, bare-bottomed holding tank for the last week of incubation and the fry-release period reduces the risk of stress-induced spitting. Fry are released at a manageable size and can be raised on baby brine shrimp and finely crushed flake. The main keeper mistake with this species is underestimating hybridisation risk: the sulphurhead's commercial appeal has generated a substantial number of 'maylandi' fish in the trade that carry Kande Island (kandeense) or other peacock genetics. Sourcing from breeders who maintain documented, unmixed lines is both straightforward and genuinely worthwhile for a species this rare in the wild.
Conservation
The IUCN Red List assesses Aulonocara maylandi as Critically Endangered (assessed 22 May 2018), under criteria B1ac(iv)+2ac(iv) — a category driven almost entirely by its minuscule, fragmented range. The assessment gives an extent of occurrence of about 43 mi² and an area of occupancy of only about 5 mi², split between the two known reefs, with an estimated fewer than 2,500 mature individuals and a declining, fluctuating population. The dominant threat is collection for the international aquarium trade: as a distinctively coloured, easily marketable peacock restricted to two small reefs, it has been heavily targeted, and the assessment cites a reported population decline exceeding 70% between the mid-1990s and 2005. Its situation is the textbook case of a narrow-range Malawi endemic whose appeal to hobbyists is itself the principal pressure on the wild stock; unlike widespread lake species it has almost no spatial buffer. Captive breeding is well established and supplies most fish in the hobby, which relieves but does not remove collection pressure, and broader lake-wide stresses — fishing intensity, sedimentation and habitat disturbance in the south-east arm — form the backdrop against which its very restricted populations must persist. The Kande Island form (whether read as Aulonocara maylandi kandeensis or as the distinct species Aulonocara kandeense) is likewise treated as Critically Endangered for the same reasons.