Taxonomy & naming
Maylandia cyneusmarginata was described by Jay R. Stauffer Jr., Nancy J. Bowers, Kathleen A. Kellogg, and Kenneth R. McKaye in their sweeping 1997 revision of the blue-black Pseudotropheus zebra complex, published in the Proceedings of the Academy of Natural Sciences of Philadelphia (vol. 148: 189–230). It was one of ten new species proposed in that paper, which simultaneously erected the new genus Metriaclima for the entire zebra complex. The holotype (PSU 3056) was collected at Nkhota Khota (now standardly written Nkhotakota) on the western shore of Lake Malawi at a depth of 3–10 ft; paratypes are deposited at ANSP (176198), MFU (27), PSU (3057), and USNM (341924).
The species' original epithet was spelled cyneusmarginatus (masculine, agreeing with Metriaclima, which Stauffer et al. treated as neuter — hence the neuter form cyneusmarginatum is also encountered). When the species is placed in Maylandia, a feminine genus, the correct form is cyneusmarginata. The spelling cyneusmarginatus is almost certainly a lapsus for cyaneusmarginatus (or more correctly cyaneomarginatus), from the Greek kyaneos, meaning dark blue; the authors' own stated etymology — 'blue margin, to note the blue marginal band in the dorsal fin' — confirms the intended root. The misspelling appears consistently through the paper and is therefore treated as the valid original spelling under the ICZN, while its intent is unambiguous.
The genus-level nomenclature has been contested for nearly three decades. Maylandia was proposed by Meyer and Foerster (1984) as a subgenus for the zebra complex. Stauffer et al. (1997) declared it a nomen nudum and replaced it with Metriaclima. Eschmeyer's Catalog of Fishes has treated Metriaclima as a junior synonym of Maylandia since January 2007 — a decision upheld in the most recent analysis, by Christopher Scharpf (Zootaxa 5620, 2025), which concluded that Meyer and Foerster's description meets the ICZN's Article 13a(i) requirements and that Maylandia therefore has priority. FishBase, GBIF, and the Catalog of Fishes use Maylandia; Konings (via Cichlid Press and Cichlid News) and the IUCN Red List use Metriaclima. Both names remain in active circulation, and the dispute is flagged in every modern Malawi cichlid reference.
The species belongs to the tribe Pseudocrenilabrini and sits within the clade of haplochromine cichlids often called the mbuna, the rock-dwelling species flock that accounts for a substantial fraction of Lake Malawi's extraordinary endemic diversity.
Morphology
Maylandia cyneusmarginata is a compact, fusiform mbuna. FishBase records a maximum standard length of 3 in for males; the IUCN assessment notes a maximum total length of approximately 4.5 in in wild adults. Females are consistently smaller, reported by malawi.si to run about 25% shorter than males. This is typical for the zebra complex, in which size dimorphism often accompanies strong color dimorphism.
Fin counts from the original description and FishBase are: dorsal spines 17–18, dorsal soft rays 8–10, anal spines 3, anal soft rays 7–8, with 10–12 gill rakers on the first ceratobranchial and 2–3 on the first epibranchial. Body depth is moderate; the species does not share the particularly elongate profile of some congeners such as Maylandia usisyae (body depth 25.9–30.6% SL), instead falling in the more typical range of the broader genus.
The defining character is the black submarginal band in the dorsal fin paired with a blue ground color on the male. Male Maylandia cyneusmarginata are a medium to deep blue on the body, with the chin ranging from white to blue depending on locality and individual, and a prominent black band just inside the outer margin of the erected dorsal fin. This band — the feature commemorated in the name — distinguishes them from the vast majority of Maylandia zebra populations, which lack the dorsal marking. The one exception within the zebra complex is the Zimbabwe Rocks form of Maylandia zebra, which carries a black dorsal margin but has a black rather than a blue cheek, allowing reliable separation.
Females are bluish-gray to gray overall and lack the dorsal-fin markings entirely. The lappets (soft projections between the dorsal spines) in males are brown, a combination that led IUCN assessor Ad Konings to note the blue marginal band and brown lappets as the primary identification characters.
Habitat
This species is a Lake Malawi endemic with one of the narrowest known ranges in the genus. It is confirmed from three sites along the Malawian western coast: Nkhotakota (the type locality, which includes the adjacent Sani area about 7 mi south), Nkhomo Reef approximately 3 mi south of the type locality, and Chidunga Rocks roughly 62 mi further south. The IUCN assessment calculates an extent of occurrence of about 2,249 mi²; with only three known locations, the species narrowly meets criterion B1 thresholds for Endangered, though continuing declines were considered uncertain at the time of the 2018 assessment.
Within those sites the fish occupies an intermediate biotope — the transition zone between dense rocky reef and open sand — characterized by medium-sized boulders and rocks scattered over a predominantly sandy bottom with a noticeable layer of sediment on exposed rock surfaces (malawi.si; Konings 2016). Vertical range runs from the shallows at 3 ft (the shallowest depth at the type locality per the original description) down to about 49 ft at deeper reef zones, depending on site. The holotype was taken at just 3–10 ft (Catalog of Fishes). In-situ water chemistry at this latitude matches the well-documented conditions of the southern and central western shore of Lake Malawi: alkaline, hard, warm freshwater with pH typically 7.7–8.6 and temperatures of 75–82 °F throughout the year, driven by the lake's deep-water chemistry and moderate seasonal thermocline (Fryer and Iles 1972; published Lake Malawi water-quality records). These values are habitat-typical for this depth zone and ecoregion rather than species-specific measurements, and should be read accordingly.
Feeding
The IUCN assessment describes Maylandia cyneusmarginata as feeding primarily from plankton, and sometimes from the aufwuchs — the biofilm of algae, diatoms, and cyanobacteria — on rock surfaces. The malawi.si species account adds that where it does graze aufwuchs it prefers sediment-free biocover on larger boulder faces, combing diatoms and fine cyanobacterial strands from the algal matrix; in very shallow areas near the wave-break it may pick up planktonic material and suspended algae dislodged into the water column.
The overall picture is a generalist that exploits both water-column plankton and benthic biofilm depending on local availability — a flexible trophic position that is not uncommon in the zebra complex. The bicuspid inner teeth and tightly-packed pharyngeal dentition are consistent with the ability to process both soft planktonic items and the periphyton mat. The species' partial dependence on sediment-free rock surfaces for aufwuchs feeding has direct conservation relevance: increased sedimentation from catchment deforestation and agriculture clogs rock surfaces and degrades this feeding resource, an active threat identified in the IUCN listing.
Mating
As in the broader Maylandia/Metriaclima complex, males of Maylandia cyneusmarginata are territorial and establish cave-centered territories among the sparse rocks of the intermediate biotope. The malawi.si account notes that territories are typically widely spaced, often 16–33 ft apart, which is consistent with the patchy distribution of suitable rock structure across a predominantly sandy substrate. Females and juveniles are largely solitary and non-territorial.
Courtship follows the mbuna pattern: males display intensely to females moving through the territory, performing lateral displays and quiver-spawning runs near the entrance of the defended rock crevice. Because males are spaced far apart relative to reef-dwelling mbuna, male–male encounters are less frequent, but when they occur they are aggressive; intraspecific male aggression is noted as significant in the malawi.si care notes. The species is described as generally tolerant toward other species — inter-specific competition at these intermediate-biotope sites is lower than on densely populated rocky reefs.
Breeding
Maylandia cyneusmarginata is a maternal mouthbrooder, the reproductive mode universal in the mbuna clade. Spawning takes place inside the male's cave, and the female alone incubates and broods the eggs and larvae. Females release the fry after approximately three to three-and-a-half weeks (malawi.si), after which parental care ceases and juveniles are abandoned. Fry tend to remain together near available rock structure.
Clutch size has not been reported in a published description for this species specifically. The IUCN assessment gives a maximum total length of about 4.5 in and notes it is an uncommon species; at that size, a clutch of roughly 20–40 eggs would be consistent with the typical output of small to mid-sized mbuna, and Fryer and Iles (1972) document small clutch sizes as characteristic of rock-dwelling haplochromines in Malawi. This figure should be understood as genus-typical and is flagged here as unpublished/inferred rather than species-specific data.
In the aquarium
Maylandia cyneusmarginata is rarely encountered in the hobby. It appears occasionally in specialist cichlid stocklists and at Malawi-focused breeders, but it is not a common trade species, and most fish offered under the name are locality variants from Nkhomo Reef. Hobbyists seeking it will usually need to source from a dedicated cichlid breeder or importer rather than a general fish shop. That said, its husbandry follows the well-established model for zebra-complex mbuna: Lake Malawi hard-alkaline water, heavy rockwork, and an all-female or strongly female-biased group structure.
A tank of at least 47–59 in in length (roughly 55–80 US gal) is the practical minimum for a colony containing one male and three to five females. Maylandia cyneusmarginata is territorial and males are aggressive toward each other and toward females outside of peak courtship activity; keeping only one male per tank is the standard approach. The extra footprint of a longer aquarium allows females to break line of sight and escape persistent aggression, which otherwise leads to chronic stress injuries and, eventually, death. Tall tanks with multiple levels of rockwork — stacked to create caves, overhangs, and broken sightlines at different depth zones — are strongly preferred. Open sand areas in the front of the aquarium replicate the intermediate-zone biotope this species actually occupies in the lake and give females neutral ground.
Water chemistry should match Lake Malawi parameters throughout: pH 7.8–8.6, total hardness above 10° dH (calcium- and magnesium-based hardness, not sodium), and temperature 75–82 °F. If tap water is soft or neutral, crushed coral or argonite substrate will buffer both pH and hardness. Dissolved oxygen should be kept high through surface movement; these fish are used to well-circulated, clear lake water, not stagnant conditions. Partial water changes of 20–30% weekly are the single most effective disease-prevention measure. This species is, like all mbuna, sensitive to Malawi bloat — a potentially fatal bacterial and osmotic condition almost always triggered by stress, poor water quality, or a diet too high in animal protein. The feeding notes in this article are consistent with the wild diet: the primary food should be spirulina-based flake or pellet and high-quality vegetable matter; meaty foods rich in mammalian proteins (bloodworm as a staple, beef heart, and similar) are a recognised cause of bloat in mbuna and should be avoided entirely, or reserved as very occasional treats.
Compatible tankmates in a species community are limited. Keeping Maylandia cyneusmarginata with other Maylandia or Metriaclima species risks hybridisation and is generally discouraged by serious keepers. It can be maintained in a mixed-mbuna aquarium alongside mbuna from different genera — Labidochromis, Cynotilapia, Iodotropheus, or moderately-sized Pseudotropheus — though any combination still requires close monitoring for aggression and for fish with sufficiently different markings that cross-spawning is unlikely. Keeping it with peaceful or soft-water cichlids is inappropriate and will stress all parties. It is fundamentally unsuitable for a general community or planted tank.
Breeding in the aquarium follows the maternal-mouthbrooding pattern described in the Breeding section. Females will hold the clutch for approximately three to three-and-a-half weeks; at completion, she can be moved to a separate holding tank to release fry safely, or the fry can be stripped at around two to two-and-a-half weeks and tumbled in an egg tumbler or fine-mesh basket. Fry are large enough at release to accept micronised spirulina flake or crushed quality cichlid fry food immediately. Because this species is uncommon in the hobby, successfully breeding and distributing quality specimens is genuinely useful to the cichlid keeper community.
Conservation
The IUCN Red List assessed this species as Near Threatened (category NT, criterion B1a) in June 2018, with Ad Konings as assessor and Jos Snoeks as reviewer (IUCN 2018: e.T61137A148846327). The previous assessments in 2006 and 2017 listed it as Vulnerable; the downlisting to Near Threatened in 2018 reflected revised spatial data and the acknowledgement that continuing declines, while possible, were not confirmed. It is found only in Malawi.
The species qualifies close to Endangered under criterion B1 on the basis of its restricted extent of occurrence (around 2,249 mi²) and its presence at only three known locations. The two primary threats identified are collection for the ornamental fish trade — it is exported internationally but at low volumes — and sedimentation driven by agricultural runoff and soil erosion in the Nkhotakota catchment. Sedimentation is particularly damaging because the species occupies intermediate-zone habitats where sediment accumulation on rock surfaces directly degrades the aufwuchs biofilm it depends on for food, and because the sediment coat reduces the visibility needed for territorial and courtship behavior. No conservation actions are currently in place; the IUCN recommends site protection, management, and population monitoring.
The broader pressures on Lake Malawi compound the species-level picture. Research reviewed by Chavula et al. and long-term fisheries data document reduced hydrological connectivity, increasing sedimentation from catchment deforestation, nutrient loading from agriculture and urban effluent, and overfishing of the small-pelagic and cichlid fisheries. The lake has warmed measurably over recent decades, affecting thermal stratification and deep-water oxygen dynamics. For a shallow, sediment-sensitive species restricted to three locations on one coast, Maylandia cyneusmarginata sits at the more exposed end of the lake's endemic-cichlid spectrum — not critically at risk today, but with little buffer against further habitat degradation.