Taxonomy & naming
Protomelas krampus was described in 2020 by Katrien Dierickx and Jos Snoeks, of the Royal Museum for Central Africa in Tervuren, Belgium, in the open-access European Journal of Taxonomy (issue 672). The genus Protomelas was erected by Eccles and Trewavas in their 1989 revision of Malawian haplochromine cichlids; it groups non-mbuna 'haps' that share a particular melanin pattern — a continuous dark midlateral stripe running from behind the gill cover to the caudal base. It was on exactly this character that Dierickx and Snoeks placed krampus in Protomelas, even though its feeding biology and upturned mouth superficially recall the unrelated paedophage genus Caprichromis. Their morphometric study separated krampus from its congeners and from the similar genera Hemitaeniochromis and Caprichromis. Strikingly, krampus departs from every other species of Protomelas — annectens, fenestratus, kirkii, labridens, macrodon, marginatus, pleurotaenia, similis, spilonotus, taeniolatus, triaenodon and virgatus — in having only a single inner tooth row on each jaw, where the others have two. The specific name krampus is a noun in apposition, taken from the Alpine folklore figure Krampus, a horned, goat-like demon who stuffs misbehaving children into a sack and carries them off; the authors chose it both as a metaphor for the fish's theft of other cichlids' broods and as an implicit reference to its head-butting (ramming) attack, echoing the goat-like name already used for the related paedophage genus Caprichromis ('goat cichlid').
Morphology
Protomelas krampus is a medium-sized, fusiform hap reaching about 7 in standard length. Its fin counts are 17 dorsal spines with 11–12 soft rays, 9–10 anal soft rays, and 31–32 vertebrae. The defining external features all relate to its predatory habit and to the formal diagnosis. The mouth is set at a strongly inclined gape — measured at 70–80 degrees, far steeper than in its relatives — so that the jaws point sharply upward, an arrangement that places the mouth in an ideal position to seize a brood the instant the fish has rammed a victim from above. The head is comparatively short and slender (length 27.8–29.2% of standard length) and the body relatively shallow (33.3–34.3% of standard length). It carries only one inner tooth row, where other Protomelas have two; the inner teeth are tricuspid, the outer teeth of the lower jaw stand straight up rather than angling forward, and there are five gill rakers on the outer epibranchial. As in all Protomelas, a single continuous dark midlateral band runs the length of the flank — the trait that anchors the species in the genus and separates it from the anteriorly spotted stripe of Hemitaeniochromis and the diagonal nape-to-tail stripe of Caprichromis. Live coloration and sexual dimorphism were not extensively detailed in the original description.
Habitat
Protomelas krampus is endemic to Lake Malawi, the ancient and biologically extraordinary rift lake shared by Malawi, Tanzania and Mozambique. The type series and additional material come from a scatter of localities around the lake: Lukoma Bay in Tanzania (the type locality), near Mara Point in Mozambique, and Otter Point, Chizumulu and the Likoma Islands, and Mazinzi Reef in Malawi — a distribution spanning the northern, eastern and southern reaches of the lake. As a paedophage that exploits the broods of other cichlids, it is tied to areas where mouthbrooding host species are abundant; in Lake Malawi that means the rocky and intermediate rock-sand habitats where the dense haplochromine and mbuna communities breed. Detailed depth and microhabitat preferences have not been published, but the species clearly operates within the well-lit, structurally complex shallow and inshore zones where brooding females congregate.
Feeding
Protomelas krampus is a paedophage — a specialist predator on the eggs and larvae of other cichlids — and its feeding behaviour is the most distinctive thing about it. The fish has been observed approaching a mouthbrooding female from above and ramming her on the snout; the impact startles the brooding female into releasing some of her eggs or larvae, which krampus then snatches before they can be recovered. Its steeply upturned mouth is the key adaptation: after striking from above, the fish is already oriented mouth-down toward the spilled brood and can grab it immediately. This head-ramming strategy is shared by a handful of unrelated Malawi cichlids — the genus Caprichromis and others — a classic case of convergent evolution toward the same unusual food source. FishBase places its trophic level at about 3.3, consistent with a carnivore feeding on small, high-protein animal prey.
Mating
No courtship sequence has been documented specifically for Protomelas krampus. Like the great majority of Lake Malawi haplochromines, it is expected to be a polygynous maternal mouthbrooder, in which males court females rather than forming pairs. In the typical Malawi-hap pattern a male develops breeding coloration and defends a small territory or display site, courting passing females with lateral displays and quivering; a receptive female spawns a small clutch with him and takes the eggs into her mouth, after which the male's role ends. The specifics of male nuptial colour, display site and territory for krampus remain to be described, and what is said here is inferred from the breeding biology of the wider flock rather than recorded for the species itself.
Breeding
Protomelas krampus has not had its reproduction studied directly, but it is reasonably inferred to be a maternal mouthbrooder like other Protomelas and the broader non-mbuna assemblage of Lake Malawi. In that mode the female incubates a relatively small clutch of large, yolk-rich eggs in her buccal cavity for roughly three weeks, releasing fully formed, free-swimming fry and continuing to shelter them in her mouth when threatened for a short period afterward. There is an irony worth noting: a fish that makes its living robbing the broods of other mouthbrooders is itself almost certainly a mouthbrooder, and so is exposed to the same risk of paedophagy from its neighbours. No clutch sizes, incubation times or fry counts have been published for krampus; these details await study.
In the aquarium
Protomelas krampus is essentially a museum and field-biology species rather than an aquarium one. Described only in 2020 from preserved and field-observed material, it has no established presence in the ornamental trade, no hobby strain or trade name, and no documented captive-breeding history. Any keeping notes can only be extrapolated from the genus and from Lake Malawi haps generally.
Protomelas as a group are medium-sized, active, hard-water cichlids that do well in large aquaria with open swimming space, sand, rockwork and the alkaline, mineral-rich water of the rift lakes (high pH and hardness, warm temperatures around the mid-20s Celsius). A paedophage like krampus would, in principle, be an awkward community member: keeping it alongside actively breeding mouthbrooders would simply give it a chance to do in the tank exactly what it does in the wild, predating the broods of its tankmates. For now it is a fish to know about for its remarkable biology rather than one to source — there is no realistic husbandry track record to draw on.
Conservation
Protomelas krampus has not been assessed by the IUCN Red List, which is unsurprising for a species described as recently as 2020. It is known from several widely separated localities around Lake Malawi — Tanzanian, Mozambican and Malawian waters — which suggests it is not a narrow-range endemic, but its true abundance is unknown and paedophages are typically uncommon, since a brood-robbing specialist must necessarily be rarer than the host species it exploits. Its conservation outlook is therefore best read at the level of Lake Malawi as a whole. The lake's cichlid flock faces mounting pressure from heavy artisanal and commercial fishing, sedimentation from deforestation in the catchment, declining water levels and the cascading effects of a warming climate on the lake's stratification and productivity. A specialist predator embedded in that community shares those risks. Until targeted survey data exist, krampus is best regarded as a Not-Evaluated, presumably uncommon endemic whose fate is bound up with the health of the lake's broader cichlid assemblage.