Taxonomy & naming
Protomelas sp. "Spilonotus Likoma" has no scientific description, no describing author, and no year of publication. The trade name follows the same convention used across the wider spilonotus group of undescribed Protomelas forms: the genus Protomelas, the abbreviation "sp." marking it as an undescribed species, and "Spilonotus" indicating that field workers and collectors consider it closely allied to the described species Protomelas spilonotus, with "Likoma" specifying the locality — the waters around Likoma Island and nearby Chilucha Reef and Ndumbi Rocks. Several geographically separate "Spilonotus" populations are recognised around Lake Malawi, each treated as a distinct, locality-specific colour form rather than as a single widespread species; how closely related the Likoma population is to Protomelas spilonotus itself, or to the other spilonotus-group trade forms, has not been resolved by formal study. Until a taxonomic revision addresses the complex, it should be treated strictly as an informally recognised, undescribed population.
Morphology
This form follows the standard Protomelas body plan — an elongate, laterally compressed haplochromine with a moderately pointed head, built along the same general lines as its close relative Protomelas spilonotus and the other undescribed spilonotus-group forms found elsewhere in the lake. Those relatives are notable for pronounced sexual dichromatism, with dominant males carrying strong blue and yellow-orange colouration set off against plainer, spot-patterned grey-brown females; whether the Likoma population matches this pattern precisely has not been documented in the literature available to us, and no dedicated colour account for this specific population is available. Size is likewise not separately documented for this form; related spilonotus-group Protomelas run to a moderately large 7–8 in in males, with females noticeably smaller, and that range is a reasonable expectation here pending direct documentation.
Habitat
Protomelas sp. "Spilonotus Likoma" is documented from the Likoma Island area of central-eastern Lake Malawi and from Chilucha Reef on the nearby Mozambique shore — a stretch of the lake characterised by large granite boulders and steep rocky drop-offs, among the best-known rocky habitat in the lake. Members of the wider spilonotus group typically favour the upper part of the water column immediately above and around large rocks rather than the rock face itself or open sand, an intermediate habitat between the lake's rock-dwelling mbuna and its purely open-water species. As with the rest of the lake, conditions are warm, hard, and strongly alkaline throughout the water column this form is likely to occupy.
Feeding
A dedicated feeding study for this population has not been published. Related spilonotus-group Protomelas are documented picking small invertebrates from the open water column above rocky habitat, a habit associated with wave-exposed, boulder-strewn coasts where turbulence stirs food-rich sediment into suspension; the Likoma population's diet is presumed to follow the same general pattern, but this has not been confirmed for this specific form. Such invertivory typically targets small crustaceans, insect larvae, and other soft-bodied animals stirred into the water column by wave action and current around exposed rock, a food source shared broadly across the lake's open-water and rock-associated haplochromines.
Mating
As in other Lake Malawi haplochromines, breeding in this genus is understood to be polygynous, with no pair bond: males hold and defend a territory or display site, typically in the upper part of rocky habitat, and females move through the area to visit colour-holding males. Related spilonotus-group populations elsewhere in the lake hold nuptial colour more or less continuously rather than only seasonally, and the Likoma population is presumed to follow the same general pattern, though this has not been separately documented. Courtship in this genus typically follows the conventional haplochromine pattern: a displaying male performs a quivering lateral show to a visiting female, and if she is receptive she follows him to his spawning site. As in most Malawi haplochromines, the male's anal fin carries egg-spot markings that draw the female to peck at them after she lays her own eggs, a behaviour that draws sperm into her mouth and fertilises the clutch she is already holding.
Breeding
Protomelas sp. "Spilonotus Likoma" is presumed to be a maternal mouthbrooder, as are all members of the genus. Related spilonotus-group forms spawn directly within the rocky habitat, in caves or crevices among the boulders or on exposed rock surfaces, rather than at sand pits. The female is expected to carry the fertilised eggs and developing fry in her mouth for several weeks before releasing free-swimming young, with no male or biparental care beyond fertilisation, but a breeding account specific to this population has not been published. At Lake Malawi's stable warm temperatures, related Protomelas typically brood for three to four weeks before releasing free-swimming fry capable of independent feeding, with no further parental care once the young are released. Whether the Likoma population follows this timeline precisely has not been documented directly, but it is the reasonable expectation for a genus in which mouthbrooding duration is fairly consistent.
In the aquarium
"Spilonotus Likoma" is a scarce, locality-specific form in the trade, generally available only through keepers and importers who specialise in Lake Malawi collection-point fish.
As with the wider spilonotus group, a tank furnished with substantial rockwork and open swimming space in the upper water column suits its likely natural habit of foraging above boulders rather than tight against the rock face or on open sand. Water should match Lake Malawi conditions closely: warm, hard, and clearly alkaline, since Protomelas species do poorly over the long term in soft or acidic water. A single male with several females is the generally recommended arrangement for Protomelas kept in modest tank volumes, since a permanently colourful male in a bare or crowded tank will pursue unreceptive females relentlessly.
Diet should follow the genus-typical template of a quality cichlid pellet supplemented with small frozen or live invertebrate foods such as daphnia and brine shrimp, in line with the water-column invertivory documented for its close relatives. Because "Spilonotus" trade forms from different Lake Malawi localities can resemble one another closely, keepers who want to preserve a pure Likoma line should avoid mixing it with other spilonotus-group fish.
Conservation
Protomelas sp. "Spilonotus Likoma" has no IUCN Red List assessment, because it has never been formally described and has no valid scientific name available to assess. This reflects its taxonomic status rather than any judgement about its population health. As a locality-restricted rocky-habitat cichlid from a well-known and heavily visited stretch of the lake, it is exposed to the general pressures common to ornamental Lake Malawi cichlids — collection at known export sites and broader shoreline disturbance — but no dedicated population data exists to characterise its actual conservation status.