Taxonomy & naming
The French ichthyologist Jacques Pellegrin described this fish in 1927 as Leptolamprologus monogramma, working from material collected at Tshikapa on the Kasai River in what is now the Democratic Republic of the Congo. The syntypes are split between the Paris museum (MNHN 1926-0348, ex Tervuren) and the Royal Museum for Central Africa at Tervuren (MRAC 19709-10); Pellegrin figured the fish the following year. The original genus name reflected his sense that the fish resembled the Tanganyikan Lamprologus, but the species was subsequently moved into Teleogramma Boulenger 1899, where it has stayed — its validity as Teleogramma monogramma has been upheld by every modern treatment, from Snoeks & De Boeck's CLOFFA account (1991) and Poll & Gosse (1995) through Stiassny & Alter (2015) and Munene et al. (2021). Teleogramma is a small, tightly knit genus of rheophilic Congo cichlids — alongside Teleogramma brichardi, Teleogramma depressa, Teleogramma gracile and the deepwater Teleogramma obamaorum (described by Stiassny & Alter in 2015) — placed in the African subfamily Pseudocrenilabrinae. The group has proven notoriously hard to resolve: traditional morphology and nuclear genes carry little signal, and it took genome-wide SNP data (Alter, Munshi-South & Stiassny 2017) to begin teasing apart cryptic phylogeographic structure and microallopatric divergence within the clade. Within that framework, Teleogramma monogramma stands somewhat apart from the lower-Congo species as the genus's representative in the more interior Kasai drainage.
Morphology
Teleogramma monogramma is a small fish, reaching about 3 in in standard length and a recorded maximum of roughly 4 in in total length — at the upper end of a genus whose members barely exceed 4 in. The body plan is the genus signature: greatly elongate and laterally compressed, with a low, tapering profile that reads as more loach- or goby-like than the deep-bodied silhouette most people associate with cichlids. This is the morphology of a fish that lives pressed to the rocks in moving water rather than hovering in open midwater, and it is paired internally with a reduced swim bladder. The single most diagnostic external feature — and the source of both the genus and species names — is the lateral line: in Teleogramma it runs as one complete, uninterrupted line along the flank, where almost all other cichlids carry a lateral line broken into two separate sections. Pellegrin singled this out as a 'very interesting peculiarity,' and the trait so misled Boulenger when he erected the genus that he initially took these fish for wrasses rather than cichlids. Coloration is generally dark and subdued — browns and greys that vanish against rock and shadow. Like its congeners, Teleogramma monogramma is strongly sexually dimorphic: in the well-studied sister species Teleogramma brichardi, breeding females develop a vivid salmon-pink flush over the belly and lower flanks while males stay a more uniform grey, the sexes also differing in the shape of the pale marking carried into the upper tail. Comparable sex differences in colour and fin pattern characterize Teleogramma monogramma.
Habitat
The species is endemic to the middle Congo basin of the Democratic Republic of the Congo, recorded from the Lulua and Kasai rivers — the Lulua being a major tributary of the Kasai, and Tshikapa, the type locality, sitting on the Kasai itself. This places it squarely in the Kasai freshwater ecoregion, the large southern sub-basin that drains the highlands south of the Cuvette Centrale before joining the Congo mainstem. FishBase classes the fish as a freshwater, demersal, tropical species, and its whole anatomy points to the same biotope its genus occupies throughout the region: fast-flowing, well-oxygenated, rocky rapids and riffles, where the fish works the bottom among stones and crevices rather than the open channel. In-situ chemistry has not been published specifically for the Kasai populations, but the interior Congo tributaries are characteristically soft and warm, running near-neutral to mildly acidic; the relevant parameters for the species are not so much a particular pH as high flow, high dissolved oxygen, and a hard rocky substrate. Depth is shallow — these are riffle and rapid fishes of the upper few metres of the water column, not deep-channel inhabitants like the molluskivorous Teleogramma obamaorum.
Feeding
No dedicated diet study has been published for Teleogramma monogramma, and its trophic role is inferred from its morphology and from its better-known congeners. FishBase places it around trophic level 3.3, consistent with a small benthic carnivore or invertivore. Teleogramma are bottom-oriented foragers that pick through the rock and gravel of fast water; in the genus, the diet is dominated by aquatic insect larvae and other small invertebrates gleaned from the substrate and crevices, with opportunistic feeding on whatever the current delivers. There is no evidence that Teleogramma monogramma is a specialist of the kind Teleogramma obamaorum is — that deepwater species evolved a distinct molluskivorous habit — so the most defensible reading is a generalized rapids invertivore working the benthos for insect larvae, micro-crustaceans and similar prey.
Mating
Teleogramma are pair-bonding cichlids, and their reproductive biology is one of the more distinctive things about the genus. Outside of breeding the fish are loosely social, often found in small groups holding feeding and shelter positions on the rocks, but reproduction reorganizes them into territorial pairs. Sexual signalling is unusually overt for such drab fish: the breeding female, not the male, becomes the colourful sex, flushing pink or salmon over the belly to advertise readiness — a reversal of the more familiar cichlid pattern. Pairs form and defend a crevice or cavity as a spawning site, and the bond is genuinely monogamous for the duration of a brood. Detailed courtship of Teleogramma monogramma itself has not been documented, but in cultivated congeners the sequence runs through mutual display at the chosen cave, the female's intensifying colour, and joint defence of the site against intruders before spawning. As with most strongly pair-bonding cave spawners, mismatched or unready fish can turn aggressive toward one another, so pairing in confined space is the delicate phase.
Breeding
FishBase records Teleogramma monogramma explicitly as a pair-bonding cave spawner, and that mode is uniform across the genus. The eggs are deposited not in the open but on the ceiling or walls of a rock crevice, cave or overhang, where the constant flow of oxygenated rapids water keeps them aerated; in the closely related Teleogramma brichardi a clutch is small — on the order of 10 to 30 eggs — and that genus-typical figure is the best available guide for Teleogramma monogramma, for which a specific clutch count has not been published. Care is biparental in character but female-led at the nest: the female tends and guards the eggs deep in the crevice while the pair defends the surrounding territory, and the young are sheltered in the rockwork after hatching. The deep, current-swept cavity does the work that mouthbrooding does in other African cichlids — hiding the brood from predators and bathing it in oxygen. Specific data on egg development time, fry size at independence, and spawning triggers for Teleogramma monogramma have not been reported; what is documented is the mode, the small clutch, and the guarded crevice nest.
In the aquarium
Teleogramma monogramma is essentially never seen in the aquarium trade; it is a rarely collected fish from the interior Kasai, and almost everything a keeper would draw on comes from experience with its lower-Congo relative Teleogramma brichardi, the one member of the genus with a real (if niche) hobby presence. That experience is directly transferable because the requirements are dictated by the shared rheophilic biology. The non-negotiable is water movement: these are fish of fast, highly oxygenated rapids, and they need strong, well-directed flow (powerheads or a river-manifold arrangement) over a clean, mature system with efficient filtration. Stagnant or warm, poorly oxygenated water is the quickest way to lose them. A tank of around 25 US gal can house a bonded pair, but a longer aquarium — 47 in or more — makes managing their territoriality far easier. The aquascape should be rock-dominated: piled stones, flat slabs and slate overhangs that create the caves, ledges and crevices the fish use for shelter and spawning, set over fine sand or smooth gravel. Plants are largely beside the point, as the natural biotope is scoured rock with little vegetation.
Temperature should sit in the warm tropical range appropriate to interior Congo tributaries (roughly the mid-20s Celsius), with soft, near-neutral to mildly acidic water; the priority is oxygenation and current rather than chasing an exact pH. Diet is straightforward for a benthic invertivore — a protein-led menu of live and frozen bloodworm, daphnia, brine shrimp and small worms, with good-quality sinking prepared foods accepted once the fish settle. Temperament is the main husbandry catch: outside breeding these are relatively peaceful, retiring bottom-dwellers best kept as a single pair (or, in a large, broken-up tank, a managed group of juveniles grown on together), but a forming or spawning pair becomes territorial, and dominant fish will bully subordinates in cramped quarters. Suitable companions are other small, current-tolerant riverine species; large or boisterous tankmates are a poor fit. Because of its rarity, anyone who actually obtains Teleogramma monogramma should treat it as a conservation-grade fish and aim to breed it rather than simply keep it.
Conservation
The IUCN Red List assesses Teleogramma monogramma as Vulnerable (VU), under criteria B1ab(iii)+2ab(iii), in an assessment dated 16 February 2009 by T. Moelants. The listing reflects a restricted range in the Kasai system combined with a continuing decline in habitat quality; the assessment identifies mining and quarrying and agricultural and forestry effluents as the principal threats, with the population trend recorded as unknown. These pressures map directly onto the Kasai's role as a major diamond- and mineral-producing region, where alluvial mining and associated sedimentation and pollution degrade exactly the clean, fast, rocky riffle habitat a rheophilic cichlid depends on. The species carries no CITES or CMS listing. The wider context is the broader vulnerability of Congo-basin rapids endemics: highly specialized current-dwellers with small ranges are disproportionately exposed to any change in flow, water quality or substrate, and several of Teleogramma monogramma's congeners face similar or sharper pressures (Teleogramma brichardi, restricted to the rapids near Kinshasa, is treated as Critically Endangered). For Teleogramma monogramma the honest summary is a narrow-range rapids specialist, formally Vulnerable since 2009, threatened chiefly by mining-driven habitat degradation in its home drainage.