Taxonomy & naming
Mylochromis sp. "Chrysogaster Line" carries no describing author, no type specimen, and no listing in Eschmeyer's Catalog of Fishes. "Chrysogaster" combines the Greek chrysos (gold) and gaster (belly), a descriptive term for golden-yellow ventral colouring; it is also, independently, the specific epithet of the described species Naevochromis chrysogaster, a different Lake Malawi haplochromine in an unrelated genus. Use of the same descriptive word for this Mylochromis population reflects a similar colour trait, not a taxonomic connection to Naevochromis, and this account does not claim one. "Line" marks it as a distinct breeding or collection line within the broader, informally recognised Mylochromis assemblage at Luwala Reef.
Morphology
Mylochromis sp. "Chrysogaster Line" is expected to share the moderately elongate, laterally compressed body plan typical of non-mbuna Malawi haplochromines in this genus. Per its trade name, males are reported to show golden-yellow colouring on the belly and lower flank; no published morphometric description, size record or full colour account exists for this population, and this account does not go beyond the trait implied by the trade name.
Habitat
This form is documented from Luwala Reef in southern Lake Malawi. As with other Mylochromis, it is expected to favour sand and sand-rock transition habitat rather than pure open rock, in the hard, alkaline water typical of the entire lake.
Feeding
No feeding study specific to this population has been published. Mylochromis as a genus is feeding-diverse: some species use molariform pharyngeal teeth to crush snails and other hard-shelled invertebrates, others pick softer invertebrates from sand or algae-covered rock, and a few are known to trail brooding females to steal eggs or fry. Without a species-specific study, no single mode can be confidently assigned to this population, and this account does not guess.
Mating
Mating behaviour has not been documented for this population specifically. Non-mbuna Malawi haplochromines in this size and habitat class typically breed on sand or at the sand-rock interface, with males establishing a display site that ripe females visit for courtship and spawning.
Breeding
As in all Mylochromis and the wider Lake Malawi haplochromine radiation, reproduction is by maternal mouthbrooding. The female takes the fertilised eggs into her mouth after spawning and carries them alone through development, releasing free-swimming fry after several weeks with no further parental care. Clutch size and brooding duration have not been recorded for this population.
In the aquarium
This form is not established in the general aquarium trade under this name, and no dedicated husbandry record exists for it. Were it kept, care would follow the general Mylochromis template: a large tank with a sand substrate and rockwork limited to the transition zone rather than dense caves, hard alkaline water matching the lake, and a varied diet suited to a likely invertebrate-leaning feeder.
Conservation
Mylochromis sp. "Chrysogaster Line" has not been evaluated by the IUCN Red List, and as an undescribed form it is not currently eligible for formal assessment. Its documented range is a single reef, and no dedicated survey of collecting pressure or habitat condition there has been published, so its status is best described as unevaluated and effectively unknown.