Taxonomy & naming
Mylochromis sp. "Liemi Small-mouth" has no scientific description, no describing author or year, and does not appear in Eschmeyer's Catalog of Fishes or FishBase. The first element of its trade name, "Liemi," is not confidently tied here to a described Mylochromis species or to a documented eponym; rather than guess at its origin, this account treats it as an unexplained field label attached to the population at Luwala Reef. The second element, "small-mouth," is a straightforward descriptive qualifier, distinguishing this form from the genus's more numerous long-snouted, wide-gaped piscivorous and sand-sifting members. A reduced mouth size of this kind, when documented in other Mylochromis species, is generally associated with a shift away from fish-hunting and toward picking smaller invertebrates from the substrate. No authority or publication date should be attached to this form.
Morphology
The defining feature signalled by the trade name is a proportionally small mouth relative to body size, setting this form apart from the genus's characteristic long-jawed sand-sifters and piscivores. Beyond that descriptive cue, no published measurements or colour account specific to this population exist. On genus-typical grounds it can be placed as a moderately elongate, laterally compressed haplochromine of roughly 5.5–7 in TL, an estimate drawn from smaller-mouthed Mylochromis species in general rather than a measurement of Luwala Reef fish. Sexual dimorphism is expected on genus-typical grounds, with breeding males more strongly coloured than drab, cryptic females, but no specific colour pattern has been documented for this form.
Habitat
The only recorded locality for this form is Luwala Reef, on the south-eastern arm of Lake Malawi. Reefs in this part of the lake typically combine rock outcrops with adjacent sand and rubble, providing the intermediate habitat many Mylochromis species use for foraging. A smaller-mouthed form is more plausibly associated with picking discrete prey items from crevices and sediment surfaces than with the broad sand-engulfing style of larger-mouthed relatives, though this has not been directly documented for the Luwala Reef population. Water in this part of the lake follows the typical warm, alkaline, well-buffered Malawi profile.
Feeding
A reduced mouth size in Mylochromis is generally consistent with a diet of smaller, more selectively taken invertebrates rather than large mollusc prey or ambushed small fish, both of which require a wider gape in the genus's specialists. This form is presumed to be a benthic micro-invertivore, picking small prey items from sand, rubble, and crevices, though no dedicated dietary study exists to confirm this for the Luwala Reef population specifically.
Mating
No dedicated courtship study exists for this form. Genus-typical expectations apply: a polygynous mating system with no pair bond, males holding loosely defended territories on sand or rubble and displaying to passing females, with a moderate level of male-male competition during breeding condition. Nothing about mouth size in particular is known to alter this general haplochromine pattern, and no departure from it has been documented for this form.
Breeding
Mylochromis sp. "Liemi Small-mouth" is presumed to be a maternal mouthbrooder, the universal strategy across Lake Malawi's haplochromine flock. Spawning would take place over a cleared patch of sand or rubble near the male's territory, with the female taking the fertilised eggs into her mouth and carrying them for several weeks before releasing free-swimming fry, with no further parental care from the male. Clutch size has not been documented for this form; a modest clutch of a few dozen eggs is a reasonable estimate by analogy with similarly sized congeners.
In the aquarium
This form has no established presence in the aquarium hobby and no dedicated husbandry record. A keeper who obtains it should follow genus-typical Mylochromis practice: a tank of at least 47–59 in, a sand or mixed sand-and-rubble substrate offering some structural cover, and water matched to Lake Malawi's chemistry — roughly 75–82 °F, pH 7.7 to 8.6, well-buffered. A smaller-mouthed, more selective invertivore of this kind is likely to do well on a varied diet of small live, frozen, or prepared invertebrate foods rather than a large-particle carnivore diet, though this has not been tested for the form specifically.
Conservation
No IUCN Red List assessment exists for Mylochromis sp. "Liemi Small-mouth", and none can until it is formally described. Its status in the wild is unassessed; the south-eastern lake faces the same general pressures affecting Malawi's inshore fish communities elsewhere, including small-scale fishing and shoreline change, but no population-specific data exist for this form. The honest position is simply that it is unassessed.