Taxonomy & naming
Mylochromis durophagus was described by George F. Turner in 2025, in 'Two new species of Mylochromis (Cichlidae) from Lake Malawi, Africa' (Journal of Fish Biology; the work was also posted as a bioRxiv preprint in 2024). The companion species in the same paper is Mylochromis rotundus. The holotype, UMZC 2016.18.13 (University Museum of Zoology, Cambridge), is a male of 3.5 in standard length, collected by scuba at Nkhata Bay on the northwestern coast of Lake Malawi in February 2016.
Turner diagnosed durophagus principally on its lower pharyngeal dentition: a heavily built bone bearing hemispherical, molariform teeth in the central-posterior field — a crushing mill. That feature places it in the small molluscivore group of Mylochromis alongside Mylochromis anaphyrmus, Mylochromis sphaerodon and Mylochromis mola, but durophagus is distinguished from them by proportions. Its head profile is less steep than that of Mylochromis anaphyrmus or Mylochromis sphaerodon, and it differs from Mylochromis mola in having a shorter snout and a deeper body. In the description, Mylochromis anaphyrmus served as the principal molariform-toothed benchmark for comparison.
The valid genus is Mylochromis Regan, 1920; the alternative Maravichromis Eccles & Trewavas, 1989 is a junior synonym (Derijst & Snoeks, 1992). As a 2025 species, durophagus enters the literature directly as Mylochromis durophagus Turner, 2025 and was not yet carried in FishBase at the time of writing. The epithet durophagus is a compound meaning 'hard-eater,' referring to the hard-shelled prey its molariform teeth are equipped to process.
Morphology
Mylochromis durophagus is a moderately sized hap; the male holotype measures 3.5 in SL, and the type material sits in that small-to-medium range typical of the genus. The body is comparatively deep — one of the features separating it from the more slender Mylochromis mola — and the head profile slopes more gently than in the steep-headed Mylochromis anaphyrmus and Mylochromis sphaerodon.
The diagnostic feature is internal and dental. The lower pharyngeal bone is heavily built and carries hemispherical, molariform (millstone-shaped) teeth concentrated in the central-posterior part of the tooth field — a robust grinding plate of exactly the kind the genus name (Mylochromis, 'millstone chromis') evokes, but which in fact only a minority of the genus actually possesses to this degree. This molarisation is the mechanical signature of a hard-shell crusher.
In colour the species shows the genus pattern. A strong dark oblique stripe runs from the nape down across the flank to the caudal fin. Females are beige with paler chest and belly and the oblique stripe prominent; mature males are darker overall, with golden spots scattered over the flank scales and dark fins marked with orange spotting. The sexes thus differ both in ground colour and in the male's nuptial ornamentation, a clear sexual dichromatism.
Habitat
Mylochromis durophagus is endemic to Lake Malawi and, on present knowledge, to the northwestern part of the lake. It is recorded from rocky shores at Nkhata Bay — the type locality — and from Mphanga Rocks near Chilumba further north. Both are shallow-water, scuba-accessible rocky sites.
Unusually for a snail-crusher, this is a rock-associated rather than open-sand species: the molluscivore Mylochromis such as Mylochromis anaphyrmus are creatures of silty sand, but durophagus inhabits rocky shores and the rock–sand interface, foraging for invertebrates over and among the rocks. That ecological setting distinguishes it from its molariform relatives and matches its deeper, more robust body. The water is the standard Lake Malawi envelope — warm (about 75–82 °F), hard and strongly alkaline (pH roughly 7.7–8.6) — and as a rocky-shore fish it occupies the shallow, well-lit zone where its scuba-collected type material was taken.
Feeding
Mylochromis durophagus is a durophagous feeder — a crusher of hard-shelled prey, as its name declares. The functional evidence is the lower pharyngeal mill of heavy, hemispherical molariform teeth, an apparatus that in Lake Malawi cichlids is reliably associated with crushing snails and other hard-bodied invertebrates. Turner inferred the diet directly from this dentition, and the species forages for invertebrates over its rocky and rock–sand-interface habitat.
This places durophagus in the small molluscivore guild of Mylochromis with Mylochromis anaphyrmus, Mylochromis sphaerodon and Mylochromis mola — a convergent specialisation that has arisen only a few times within the genus, against a much larger group of generalist sand-sifters and a low-trophic-level planktivore wing. What sets durophagus apart ecologically is that it brings the crushing apparatus to a rocky-shore setting rather than the silty sand its molariform relatives favour, implying it exploits the hard-shelled invertebrate fauna of the rocks and the rock–sand margin. No direct gut-content study has yet been published; the diet is inferred from dentition and habitat, as stated in the original description.
Mating
Mylochromis durophagus is, like all Lake Malawi haplochromines, expected to be a polygynous maternal mouthbrooder without a lasting pair bond. The genus and lake pattern is lek-like: dominant, brightly coloured males establish and defend territories — here, on or among the rocks of the shallow zone — and court a succession of females, each of which selects a mate from several before spawning.
The pronounced male coloration described for the species (dark body, golden flank spots, orange-marked fins) is exactly the kind of nuptial signalling used in haplochromine courtship, and the standard egg-spot mechanism is expected: the male displays his anal fin, whose egg-mimicking spots draw the female to mouth at them as she collects her eggs, fertilising the clutch in her buccal cavity. No species-specific courtship observations have been published for durophagus, so this account reflects the genus-typical system inferred from its biology and coloration.
Breeding
Breeding is maternal mouthbrooding in the haplochromine pattern. The female spawns over a male's territory, takes the fertilised eggs into her mouth at once, and broods them through egg and larval development — fasting throughout — before releasing free-swimming fry. There is no male parental care and no care after release.
No clutch sizes, incubation periods or fry data have been published for Mylochromis durophagus, which was described only in 2025 from preserved type material rather than from breeding observations. For a fish of this size, broods are likely modest — on the order of a few dozen eggs, by comparison with similarly sized congeners — but that is an inference from genus-typical fecundity, not a measured figure for durophagus. Incubation in comparable lake haps lasts two to three weeks, and generation length across the flock is generally estimated at two to three years.
In the aquarium
Mylochromis durophagus is not in the aquarium hobby. Described in 2025 from scuba-collected specimens at remote northwestern reefs, it has no trade presence and no record of being kept or bred. Any husbandry guidance is extrapolated from its known habitat and from the care of comparable rock-associated Malawi haps, and should be treated strictly as such.
Were it ever maintained, it would call for a large Malawi-style aquarium combining rockwork with an adjacent open sand area — reflecting its rock–sand-interface habitat — rather than either a bare sand tank or a solid rock wall. Water must match the lake: pH about 7.8–8.6, temperature 75–82 °F, moderately hard to hard, with strong filtration and regular partial water changes. A molluscivore is well served by occasional hard-shelled foods — small snails, shrimp and similar invertebrates — alongside a quality Malawi pellet staple; as with all alkaline-water cichlids, the rich meaty diets linked to 'Malawi bloat' should be limited. Tankmates should be peaceful-to-moderate haplochromines and peacocks of similar size rather than aggressive mbuna. One male per tank avoids chronic territorial conflict. In sum, this is a newly described fish of scientific interest with no captive track record, and the above is a reasoned framework rather than a proven recipe.
Conservation
Mylochromis durophagus has not been assessed by the IUCN Red List — unsurprisingly, as it was described only in 2025 — so its status is honestly Not Evaluated. No formal conservation category, fishery interest or CITES listing applies.
Its conservation interest is, however, easy to frame. It is presently known from just two northwestern rocky localities (Nkhata Bay and Mphanga Rocks near Chilumba), making it, on current data, a narrow-range endemic — and rocky-shore Malawi cichlids are characteristically restricted to particular reefs, so a small known range may reflect genuinely limited distribution as much as limited sampling. The lake at large is under documented stress: Chavula and colleagues (2023, Journal of Great Lakes Research) describe rising surface temperatures, strengthening stratification that suppresses nutrient mixing, heavy sediment and nutrient loading from deforested catchments, and over-fishing that has collapsed the chambo fishery. For a rock-associated invertivore, sediment loading that smothers rocky substrate and its invertebrate fauna is the most directly relevant threat. Until the species is surveyed more widely and formally assessed, it is best regarded as a recently discovered narrow-range endemic whose conservation status remains to be determined.