Taxonomy & naming
Mylochromis sp. "Incola Mumbo" has no scientific description, no describing author or year, and does not appear in Eschmeyer's Catalog of Fishes or FishBase. Its trade name follows the standard resemblance-plus-locality convention: "incola" refers to Mylochromis incola, described by Ethelwynn Trewavas in 1935 and named from the Latin for "inhabitant," likely alluding to its life among the lake's Vallisneria beds; "Mumbo" points to Mumbo Island, a well-known southern-lake site. The form here is documented at Boadzulu Island, a separate southern-lake island, and is presented as resembling M. incola closely enough to carry its name informally without having been confirmed as the same species by direct examination. Until that work is done, no authority or date should be attached to it.
Morphology
As a form allied to Mylochromis incola, this fish is expected to share that species' general build: a moderately elongate, laterally compressed haplochromine reaching a comparable size, with M. incola documented at close to 8 in TL. Breeding males of M. incola are noted in the trade for warm golden nuptial tones, a pattern consistent with its Latin epithet's suggested association with shallow, vegetated habitat. No colour account specific to the Boadzulu Island population of this form has been published, so the warm-tone expectation should be read as an inference from the described relative rather than a documented fact for this fish. Females and non-breeding fish are expected to be cryptically coloured, following the genus-wide pattern.
Habitat
The recorded locality for this form is Boadzulu Island, in the southern part of Lake Malawi near Mangochi, close to the lake's outflow into the Shire River. Mylochromis incola is documented from shallow, vegetated inshore habitat throughout the lake, particularly among beds of Vallisneria and other submerged plants; Boadzulu Island's shoreline mixes rocky habitat with sandy bays that can support similar vegetated margins in places. Whether this form occupies the same specific vegetated-inshore niche as M. incola at Boadzulu has not been separately documented.
Feeding
Mylochromis incola forages among decaying plant material and the invertebrates it shelters, taking small invertebrates and probably insect larvae from the leaf litter and sediment of its vegetated habitat. This form is presumed to feed similarly, given the resemblance the trade name implies, though no dedicated study of its diet at Boadzulu Island exists. As with other vegetation-associated haplochromines, it is not expected to be a specialised piscivore or molluscivore.
Mating
No dedicated courtship study exists for this form or, in detail, for Mylochromis incola itself. Genus-typical expectations apply: a polygynous mating system with no pair bond, males establishing loosely defended territories near cover or vegetation and displaying to passing females, and moderate levels of male-male aggression during breeding condition. The vegetated, structurally complex habitat associated with M. incola may allow smaller, more dispersed territories than the open-sand species in the genus, but this has not been documented specifically for the Boadzulu Island form.
Breeding
Mylochromis sp. "Incola Mumbo" is presumed to be a maternal mouthbrooder, the universal strategy across Lake Malawi's haplochromine flock. Spawning would take place near cover in shallow inshore habitat, with the female taking the fertilised eggs into her mouth and brooding 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 moderate clutch of a few dozen eggs is a reasonable estimate by analogy with M. incola and similarly sized congeners.
In the aquarium
This form is uncommon in the trade and has no dedicated husbandry record separate from Mylochromis incola generally. A keeper who obtains it should provide a tank of at least 47–59 in, a sand substrate with some structural cover — rockwork or hardy, robust plants able to tolerate hard alkaline water — and water matched to Lake Malawi's chemistry: roughly 75–82 °F, pH 7.7 to 8.6, moderately hard to hard. It is expected to be reasonably peaceable by Malawi standards, suitable for mixed-species hap communities rather than mbuna, though this has not been tested for the form specifically.
Conservation
No IUCN Red List assessment exists for Mylochromis sp. "Incola Mumbo", and none can until it is formally described. Its described relative, Mylochromis incola, has been assessed as Least Concern by the IUCN, being widespread across the lake's vegetated inshore habitat, but that status does not automatically extend to this Boadzulu Island form. Vegetated inshore habitat around populated southern-lake shorelines faces pressure from shoreline development and small-scale fishing; whether this specific population is affected is not documented. The honest position is that it is unassessed.