Taxonomy & naming
Ethelwynn Trewavas described this species in 1935 as Haplochromis spilostichus in her landmark synopsis of the cichlid fishes of Lake Nyasa (now Lake Malawi), published in the Annals and Magazine of Natural History. The description was based on a single specimen — the holotype, catalogued BMNH 1935.6.14.1459 — taken at Monkey Bay on the southeastern arm of the lake. For over five decades the fish remained in the broad, catch-all genus Haplochromis. Eccles and Trewavas' 1989 monograph Malawian Cichlid Fishes moved it to Sciaenochromis, recognising the fish's elongate, predatory build as characteristic of that lineage. Turner and Howarth (2001) and Konings (2016) subsequently placed spilostichus in Mylochromis, and that is the combination accepted by Eschmeyer's Catalog of Fishes (updated May 2026). The valid name is therefore Mylochromis spilostichus (Trewavas, 1935), with Haplochromis spilostichus Trewavas 1935 and Sciaenochromis spilostichus (Trewavas 1935) as synonyms. The species was never placed in Maravichromis; that genus, erected by Eccles & Trewavas (1989) for a different cluster of sand-associated haplochromines, was independently synonymised with Mylochromis by Derijst and Snoeks (1992, Cybium 16(2):173), but spilostichus travelled from Sciaenochromis directly to Mylochromis. No subspecies or recognised geographic colour morphs have been formally described, though Konings notes the species at particular reefs including Makokola Reef and Luwala Reef in the southern arm. No settled English common name exists for this fish in the hobby or trade; it is sold, when available at all, under its binomial or as 'Mylochromis spilostichus Makokola'.
Morphology
The body is elongate and fusiform — streamlined in the way of a fish that makes its living by acceleration over open ground rather than manoeuvring through rocks. The head is large relative to body depth, the snout moderately pointed, and the terminal mouth wide, with the maxilla reaching to approximately the front edge of the orbit. Jaw teeth are conical, suited for gripping rather than grinding — a contrast with the molariform pharyngeal dentition that gives the genus its name (mylo, mill). The diagnostic marking is an oblique series of roughly ten dark bars or blotches on the upper half of the flanks, running from the nape down and back to the base of the caudal fin; the spots vary in regularity and size between individuals, a feature that has led to some confusion with the related Mylochromis gracilis, in which the diagonal band is composed of more uniform, evenly-spaced small spots. The dorsal fin counts approximately XVIII spines and 12 soft rays; the anal fin III spines and 10 soft rays (Trewavas 1935). FishBase records the maximum total length as 8.5 in (Maréchal 1991, CLOFFA vol. 4), though Konings' field observations from the lake give a typical adult size of about 10 in TL for well-grown males. Sexual dimorphism is evident: breeding males carry an intense iridescent blue-green sheen with rows of yellow spots on the flanks and bright yellow in the anal fin, while females and non-breeding males are a drabber olive-silver with the spotting pattern less vivid but still recognisable. Males also tend to run larger than females.
Habitat
Mylochromis spilostichus is a lacustrine endemic confined to Lake Malawi (also named Lake Nyasa in Mozambique and Lake Niassa in Tanzania). It is distributed through the southern part of the lake — with documented records from the southeastern arm, the area around the Nankhumba Peninsula, Makokola Reef, Luwala Reef, and Mbenji Island — and the IUCN assessment notes a range spanning Malawi, Mozambique, and Tanzania, reflecting a more lake-wide but patchy presence. FishBase places its depth range at 59–230 ft, with field observations by Konings finding it hunting over sand at roughly 115 ft at Makokola Reef; the species' preference for deeper sandy zones means it is rarely encountered by shallow-reef observers. The substrate is open sand, sometimes near the edge of rocky outcrops that provide structure for spawning and cover. Like all Lake Malawi cichlids, it inhabits clear, warm, alkaline water: the lake's surface layers run 75–82 °F seasonally, with pH typically 7.7–8.6 and conductivity around 210–285 µS/cm. Precise in-situ chemistry measurements specific to the depths this species occupies have not been published; the values above are habitat-typical for the southern arm based on the lake-wide monitoring literature (Chavula et al. 2023).
Feeding
Mylochromis spilostichus is an active piscivore. FishBase assigns it a trophic level of 4.2, consistent with a higher-order fish-eater, and the species account based on Turner & Howarth (2001) and field observations notes that it feeds by chasing small fish close to the substrate. Konings' field work at Makokola Reef describes individuals observed hunting over sandy bottoms, working the interface between open sand and the rock-sand margin where juvenile cichlids concentrate. This is a pursuit predator: the elongate, torpedo-shaped body generates rapid bursts of acceleration, and the terminal, wide-gape mouth snaps up prey fish before they can reach the rocks. This feeding mode places Mylochromis spilostichus in the same broad ecological guild as other Malawi sand-flat piscivores — Nimbochromis, Dimidiochromis, and some Tyrannochromis — though its smaller maximum size and sand-only habitat separate it ecologically from those heavier ambush predators.
Mating
Males of Mylochromis spilostichus are territorial during the breeding season, excavating and defending shallow spawning pits in sandy substrate near rocks. A territorial male in full breeding colour — deep blue-green with vivid yellow spots and a bright ocellate anal fin — holds his pit against rival males and courts passing females with fin displays and circling behaviour typical of Lake Malawi haplochromines. Females are not permanently resident in a male's territory; they cruise the sandy flat, assessing multiple displaying males before committing to spawn. The species is not reported to form long-term pair bonds: spawning is a relatively brief interaction, after which the female immediately begins brooding and the male returns to defending his territory and courting further females. Males are capable of significant aggression toward other males and toward other species that approach too closely — a useful piece of context for aquarium keepers designing a tank community.
Breeding
Mylochromis spilostichus is a maternal mouthbrooder, the reproductive strategy shared by the great majority of Lake Malawi's haplochromine cichlids. After spawning over the male's pit, the female collects the eggs in her buccal cavity and broods them without further assistance from the male; the male plays no role in incubating or guarding the fry. Incubation period in Lake Malawi mouthbrooders of comparable size typically runs three to four weeks at lake temperatures (75–82 °F), after which the female releases free-swimming fry that she may still call back into her mouth for a short period at signs of danger. Clutch sizes have not been formally documented for this species; the IUCN assessment notes a generation length of 2–3 years and flags the species as reaching sexual maturity at approximately 4 in standard length, consistent with a moderately fecund cichlid whose individual broods are likely in the range of 30–60 eggs, comparable to similar Malawi haplochromines of like size — though that figure is genus-typical inference, not a published count for spilostichus itself. In aquarium settings, breeding follows the same maternal mouthbrooding pattern; see the aquarium section below.
In the aquarium
Mylochromis spilostichus is rarely kept in the hobby and seldom offered by specialist cichlid importers; most hobbyists who have kept it obtained it through dedicated Malawi-cichlid networks rather than the general trade. That obscurity is not a reflection of difficulty so much as low commercial profile: as a deeper-water sand-dwelling species without the neon colour-pop of the mbuna or the mass-market appeal of Aulonocara peacocks, it simply does not move in volume. Keepers who have worked with it consistently describe it as a manageable but space-demanding fish.
The minimum tank footprint for a single group of Mylochromis spilostichus is typically quoted at 80–105 US gal, with a long, wide base preferred over height — a 5 ft or 6-foot tank is a reasonable target. The single most important setup detail is substrate: a bed of fine, light-coloured sand at least 2–3 in deep is essential. In the wild this fish hunts over open sand and males excavate sandy pits for spawning; without sand it will show stressed, unnatural behaviour, and males rarely come into breeding condition properly. A small amount of rockwork toward the back or ends of the tank provides sight-breaks and lets subdominant fish escape line-of-sight from an aggressive male, but the central floor area must be open sand. Vigorous filtration — turning the volume at least four to six times per hour — is necessary both because large active piscivores produce a significant bioload and because Lake Malawi water is famously clear and well-oxygenated.
Water parameters should match the lake: temperature 75–81 °F, pH 7.8–8.6, and hard alkaline water with a general hardness above 10 °dH and carbonate hardness (KH) above 6. Malawi cichlid keepers commonly use a commercial Malawi salt mix or a blend of sodium bicarbonate and calcium/magnesium salts to maintain buffering; tap water in many regions must be adjusted. Stability matters more than hitting exact numbers — wide pH swings are more harmful than sitting at 8.0 versus 8.3.
Because this is an active piscivore, tankmate selection needs care. Small fish — anything that fits in the mouth, which for an adult male means fish under roughly 2–2.5 in — will simply be eaten. Suitable companions are other large Lake Malawi haplochromines of similar size and comparable aggression: Copadichromis, other mid-sized Mylochromis species, Nimbochromis, and large Aulonocara are common pairings in specialist tanks. Mbuna (rock-dwelling cichlids) are not ideal companions: mbuna are adapted to high-algae diets and can suffer digestive problems when kept with fish demanding protein-heavy feeding regimes; more practically, mbuna harassment of a brooding female can cause her to spit a clutch prematurely. Multiple males of the same species will fight seriously unless the tank is large enough to hold genuine territories; most keepers run one male to several females.
Mylochromis spilostichus is a carnivore and should be fed accordingly — high-quality cichlid pellets with a protein content above 40%, supplemented with frozen foods such as krill, mysis shrimp, and silversides. The single most common cause of death in Malawi haplochromines in the hobby is Malawi bloat, a rapid and often fatal digestive condition typically triggered by overfeeding of high-plant-content foods, fillers, or live feeder fish of uncertain quality. Dried pellets with no high-carbohydrate fillers, fed in moderate amounts once or twice a day, are safer than indiscriminate live-food feeding. Breeding in captivity follows the same maternal mouthbrooding pattern described in the Breeding section: a conditioned female will spawn over a pit the male excavates in the sand, collect eggs immediately, and brood for roughly three weeks at aquarium temperatures. Experienced keepers typically strip the female at 16–18 days and rear the partially developed fry artificially, avoiding the risk of a stressed female spitting or swallowing the clutch.
Conservation
Mylochromis spilostichus is assessed as Least Concern on the IUCN Red List (assessed 20 June 2018; assessors: J. Kazembe, A. Konings, P. Makocho, A. Mailosi). The justification is a wide distribution across Lake Malawi's sandy habitats, no documented major population decline, and an estimated extent of occurrence of roughly 29,373 mi². Population trend is listed as unknown — there is no confirmed evidence of stability or decline, which limits the usefulness of the current assessment as an early-warning tool. Known threats are subsistence fishing (it is taken as bycatch in artisanal nets) and low-level collection for the ornamental trade. Habitat degradation from sedimentation is flagged as a concern: sedimentation driven by deforestation and agricultural runoff around the lake basin can degrade the open sandy bottoms this species depends on for both foraging and spawning. That broad threat sits within a sobering wider picture. Lake Malawi is a UNESCO World Heritage Site (inscribed 1984) for its extraordinary cichlid diversity — over 800 cichlid species, more than 98% endemic — but the lake is under accelerating pressure. Chavula et al. (2023, Journal of Great Lakes Research 49:102241) document the basin's key stressors: a rapidly growing human population, persistent poverty, intensive artisanal and commercial fishing, land-use change driving sedimentation and nutrient loading, and the emerging effects of climate warming on thermal stratification and productivity. The UNESCO World Heritage Committee has repeatedly flagged the National Park's state of conservation, noting that overfishing affects larger cichlid species even within the park's protected waters (Natural World Heritage Sites review). For Mylochromis spilostichus specifically, the current LC status is appropriate — it is not in immediate crisis. But as a demersal sand-flat specialist at depths the lake's subsistence fisheries do reach, and in a system facing decade-scale habitat degradation, continued monitoring matters more than a single Least Concern label might suggest.