Taxonomy & naming
Otopharynx sp. "Auromarginatus Margrette" is an undescribed Lake Malawi cichlid, known only by this trade name on the malawi.si database and in specialist hobby circles. It has no valid scientific name, no describing author, and no publication year, and none of these should be attached to it. The label follows the open-nomenclature convention of pairing the genus with a descriptive tag in quotation marks to flag a field-recognised but taxonomically undiagnosed population.
The first part of the tag, "Auromarginatus," borrows the specific epithet of Otopharynx auromarginatus, a formally described species in the same genus whose name (from Latin aurum, "gold," and marginatus, "margined" or "edged") refers to gold-edged fin markings. Its use here signals that this form is regarded as resembling or allied to that species, not that it has been confirmed as the same fish under a different name. The second element, "Margrette," is not explained in any source consulted for this article; it may be a personal or locality tag, but no confirmed derivation can be offered.
Otopharynx was erected by Regan in 1920 and today holds a substantial number of Lake Malawi haplochromine species, most associated with sandy or intermediate habitat rather than the strict rock specialisation of the mbuna. Because this form has never been formally studied, its precise relationship to O. auromarginatus and to the rest of the genus remains unresolved.
Morphology
No published measurements or colour account specific to Otopharynx sp. "Auromarginatus Margrette" were found in the sources consulted for this article. Genus context: Otopharynx species share a moderately elongated, laterally compressed haplochromine body, generally larger-bodied than the mbuna, with adult size across the genus commonly in the low-to-mid teens of centimetres; the related O. auromarginatus and similar mid-sized Otopharynx typically run roughly 5–6.5 in total length, a figure offered here as a genus-typical estimate rather than a measurement of this form.
The trade name's reference to O. auromarginatus implies gold-edged fin markings, presumably on the dorsal and/or caudal fin margins of breeding males, in keeping with that species' name. Whether this form shows that trait in the same way, and how its overall colouration otherwise compares, has not been documented in the sources available here and should not be assumed beyond the name's implication.
Habitat
All four documented localities for this form — Likoma Island, Maingano Island, the Mbamba Islands, and Ndomo Point — sit within the Likoma Island group, a small Malawian archipelago in the middle of Lake Malawi that is surrounded by Mozambican waters, roughly 12 mi from the nearest Malawian mainland shore. This isolation, combined with the islands' extensive rocky and boulder-strewn margins, has made the Likoma group a locally distinct cichlid assemblage relative to the nearby mainland coast.
Otopharynx as a genus is generally associated with sandy bottoms and the transitional zone between open sand and rock rather than pure rock habitat, though the genus is ecologically diverse. Lake Malawi's water chemistry in this zone runs broadly 24-28 degC and pH 7.7-8.6, hard and alkaline, with Otopharynx habitat typically found somewhat deeper than the shallow mbuna zone, commonly in the range of roughly 26–98 ft depending on the species and site. No site-specific depth record exists for this particular form.
Feeding
Feeding has not been documented specifically for Otopharynx sp. "Auromarginatus Margrette." The genus as a whole is ecologically varied: many Otopharynx species forage over sand and rock margins for small invertebrates and algal material, picking rather than grazing in the concentrated manner of mbuna, while a smaller number of species take harder prey such as snails using robust pharyngeal dentition. Without a study of this specific population, it is safest to describe it only as a generalist forager typical of the genus rather than to assign it a narrower feeding niche that has not been confirmed.
This more generalist, less rock-bound feeding style is one reason non-mbuna haplochromines like Otopharynx can share reef habitat with dense mbuna populations without competing directly for the same algal turf: rather than grazing fixed rock surfaces, they range more widely over sand and rock margins for a broader mix of food items.
Mating
Social structure has not been documented for this form. Non-mbuna haplochromines such as Otopharynx are generally understood to be polygynous, with males establishing display territories — sometimes simple sand-floor sites rather than defended rock caves — that they hold to attract passing females, in the lek-like pattern typical of the lake's haplochromine radiation. Females are not territorial and visit displaying males when ready to spawn. No detail specific to this population's courtship or territorial behaviour has been published.
Courtship in this style of haplochromine typically involves the male performing a quivering lateral display and leading an approaching female toward his spawning site, a pattern shared broadly across the lake's mouthbrooding cichlids regardless of habitat. Because territories away from strict rock habitat are often less permanent than a mbuna's defended cave, a displaying male may relocate his site if local conditions change — a detail not documented specifically for this population but consistent with the wider ecology of lek-breeding, sand-associated haplochromines.
Breeding
As with every Lake Malawi haplochromine, this form is presumed to be a maternal mouthbrooder. A female takes eggs into her mouth at the male's spawning site, is drawn to fertilise them by mouthing the egg-spot markings on his anal fin, and broods the clutch orally for roughly three to four weeks before releasing free-swimming fry, with no further parental care afterward. No clutch size has been documented for this specific form; genus-typical broods for mid-sized Otopharynx are expected to run to several dozen eggs, larger on average than the smaller clutches typical of mbuna.
The egg-spot mechanism behind this process is one of the more distinctive features of Lake Malawi cichlid biology: the yellow-orange markings on the male's anal fin closely mimic the fish's own eggs in size and colour, and the female's instinct to gather stray eggs into her mouth is what draws her toward the male's vent, where she takes in sperm instead. This indirect fertilisation method, shared across virtually the entire haplochromine radiation of the lake, lets fertilisation happen without either fish releasing gametes into open water where they would be exposed and vulnerable.
In the aquarium
Otopharynx sp. "Auromarginatus Margrette" is a rare fish in the trade, more likely to surface through specialist Malawi cichlid importers who deal directly with Likoma-area collectors than through general retail. No form-specific husbandry literature exists, so the guidance here follows general Otopharynx and Lake Malawi haplochromine practice.
A tank of at least 47–59 in suits a species this size, aquascaped with a sand substrate and scattered rock providing cover without the dense wall-to-wall rockwork typical of a pure mbuna setup, reflecting the genus's more open-habitat tendency. Water must replicate Lake Malawi's chemistry: hard and alkaline, pH roughly 7.8-8.6, temperature 24-28 degC. Diet should be more varied than a strict mbuna's: a quality cichlid pellet as a staple, supplemented with small frozen or live invertebrates such as chironomid larvae, brine shrimp, and daphnia, alongside some plant-based material.
A single male with several females is the standard low-conflict arrangement for a lek-breeding haplochromine of this kind. As with all undescribed locality forms, keep it apart from other Otopharynx populations, and especially from other auromarginatus-allied forms, to prevent hybridisation and preserve its value as a distinct trade form.
Conservation
Otopharynx sp. "Auromarginatus Margrette" has never been formally described and so carries no IUCN Red List assessment of any kind; evaluation requires a valid scientific name. Its recorded range is confined to the Likoma Island group, a small and geographically isolated archipelago, which makes any population there inherently more vulnerable to localised pressure than a widely distributed mainland form, even though no specific threat has been documented for this population. The islands share the general pressures affecting Lake Malawi's inshore habitat: sedimentation, warming surface waters, and the ornamental and food fisheries operating in the area. Formal description would be the prerequisite for any future Red List evaluation; until then its status is properly recorded as unassessed.