Taxonomy & naming
Lacustricola nitida was formally described by Nagy, B. and Chocha Manda, A. in 2020, in the journal Ichthyological Exploration of Freshwaters (IEF-1154, 11 pp.). The type locality is given as a small temporary stream in the Lufupa River system, a left-bank tributary of the upper Lualaba drainage in Lualaba province, Democratic Republic of Congo. The species epithet nitida is Latin for 'bright', 'polished', or 'shining', an apt reference to the gleaming blue iridescence of the body scales in live fish.
The authority citation (Boulenger, 1906) refers to the original placement of the genus-group; the valid name for the genus Lacustricola follows the treatment in Eschmeyer's Catalog of Fishes. Nagy and Chocha Manda distinguished L. nitida from its closest relative, L. matthesi, primarily on the basis of male fin markings — the dorsal and anal fins in nitida are hyaline and without patterning, whereas those of matthesi bear yellow colouration with dotted stripes — and on differences in the number of exposed neuromasts in the supraorbital sensory system (three in nitida, four in matthesi), along with supporting morphometric differences and pectoral fin ray counts. Killi-Data (entry 546) confirms the original publication and places the species in the upper Lualaba province of the Congo basin. The species is assigned to the family Procatopodidae, the African lampeyes, within the order Cyprinodontiformes.
Morphology
Lacustricola nitida is a slender, small-bodied lampeye reaching a maximum recorded total length of approximately 1 in. The body is elongate and laterally compressed in the typical Lacustricola fashion, with a pointed snout, upturned mouth, and large eyes. The most immediately distinctive feature is the iridescent blue of the flanks: metallic blue spots positioned at the centres of individual scales produce longitudinal lines of reflected light along the body, creating a fish that appears to glow with a polished, metallic blue-green sheen under ambient light. This body colouration is shared with the closely related L. matthesi; the two species overlap conspicuously in this trait.
The clearest way to distinguish L. nitida from L. matthesi lies in the unpaired fins. In L. nitida the dorsal and anal fins are hyaline — essentially clear and unpatterned — giving the fish a clean, unadorned appearance beyond the body iridescence. The supraorbital light organ, the defining feature of the lampeye group, sits just above and behind the eye; in Lacustricola species this patch refracts ambient light to produce a blue-green flash. Sexual dimorphism is typical for the genus: males are more intensely coloured with brighter iridescence, while females are plainer and rounder-bodied when gravid.
Habitat
The type locality of Lacustricola nitida is a small stream in the Lufupa River system, a left-bank tributary feeding the upper Lualaba drainage in Lualaba province, Democratic Republic of Congo. The Lualaba is the upper Congo River, flowing north through the high plateau of southeastern DRC before broadening into the vast central Congo basin. The Lufupa is a relatively small tributary in the upper reaches of this system, and the original collection was made in what is described as a temporary or seasonal stream — a water body that may partially dry or contract markedly in the dry season, though the species itself is a non-annual fish that persists through wet-season reclusion rather than via diapausing eggs.
Water chemistry data specific to the Lufupa system are not available in the literature for this species; general data from related Congo basin killifish studies suggest the upper Lualaba catchment experiences stable stream temperatures in the range of approximately 68–73 °F year-round, with clear, well-oxygenated water that is likely soft and acidic to neutral (estimated pH 6.0–7.0), typical of upland Congo basin forest and savanna streams draining ancient Precambrian substrates with low buffering capacity. The streams here are not blackwater in the strict sense but are generally low in dissolved minerals. Dense riparian and aquatic vegetation provides the fine-leaved structure and root mats among which lampeye killifish typically spawn and seek shelter.
Feeding
No specific dietary data for Lacustricola nitida are recorded in the available literature. By analogy with other small lampeye killifish of the genus and family, the diet in the wild is assumed to consist chiefly of small invertebrates: microcrustaceans (cladocerans, copepods, ostracods), chironomid and other insect larvae, small worms, and whatever other small arthropods are present in the water column or near the surface film. The upturned mouth is well adapted for feeding at and just below the water surface, targeting emerging insect pupae and small surface-drifting invertebrates.
In captivity, lampeyes in general accept a range of small live and frozen foods readily: Artemia nauplii and adult brine shrimp, Daphnia, micro-worms, and small frozen bloodworm and Cyclops. Dry foods can be accepted if suitably fine-grained. Because of their small adult size, appropriately sized prey is important: standard community pellets are typically too large for routine feeding, and finely milled dry foods or small live cultures are preferable as dietary staples.
Mating
Lacustricola nitida, like all members of the genus Lacustricola and the broader lampeye group (family Procatopodidae), is a non-annual, continuous spawner. It does not produce diapausing eggs designed to survive a dry season buried in substrate; instead it breeds throughout the year in its permanent or semi-permanent stream habitats, depositing small numbers of adhesive eggs among fine-leaved aquatic plants, moss, and root tangles over an extended period rather than in a single mass-spawning event.
Male lampeyes use their conspicuous supraorbital light organs and body iridescence in courtship display, orienting alongside females and flashing their flanks to elicit spawning. The mating sequence is brief: the male positions alongside or slightly beneath the female, and eggs and sperm are released together in single or small multiple-egg releases. The adhesive eggs attach to plant surfaces or fine root structures, where they develop without parental attention. Because spawning is spread across time, gravid females carry only a moderate number of ripe eggs at any one moment, consistent with the low-clutch, high-frequency reproductive strategy typical of non-annual lampeyes.
Breeding
In the aquarium, Lacustricola nitida is expected to breed in the manner typical of non-annual Procatopodid lampeyes. A well-planted or mop-equipped breeding tank of 5.5–10 US gal, maintained at approximately 72–75 °F with soft to moderately hard, slightly acidic to neutral water, provides suitable conditions. Fine-leaved plants such as Java moss, hornwort, or commercial spawning mops serve as egg deposition sites. The pair or a small group can be maintained together; because spawning is continuous and spread over time, no distinct spawning season needs to be induced.
Eggs are adhesive and small, typically developing over one to two weeks depending on temperature. Adults may consume eggs if they encounter them, so providing dense plant cover or regularly checking and removing mops to a separate hatching vessel improves fry yield. Fry are tiny on hatching and require infusoria, paramecia, or equivalent micro-live foods as first foods for the first week or more before they can accept Artemia nauplii. Growth is relatively steady in small lampeyes; young fish typically reach adult size within three to four months under good feeding conditions. No parental care of any kind is observed in this group.
In the aquarium
Lacustricola nitida was described only in 2020 and is not yet established in the general aquarium trade. Its small size (to 1 in) and elegant iridescent blue body colouration make it an appealing subject for specialist killi-keepers or small nano-aquaria enthusiasts, but availability will realistically be limited to specialist killifish societies and the occasional import from Congo basin collections. The fish is best kept in a species aquarium or in a peaceful nano community of similarly sized non-predatory fish that share comparable water requirements.
A tank of 10–15 US gal with dense fine-leaved planting, a dark substrate, and subdued lighting shows the blue iridescence to best effect and reduces stress in these inherently shy, small fish. Filtration should be gentle — a sponge filter is ideal — since strong currents are inappropriate for a fish from small, sheltered stream backwaters. Water temperature in the range of 68–75 °F is appropriate given the upland provenance of the species. Water changes of 20–30 % per week maintain quality without abrupt parameter shifts. The species poses no compatibility problems within its size class, though it should not be kept with fish large enough to view it as prey.
Conservation
Lacustricola nitida has not been evaluated by the IUCN Red List. As a species described only in 2020, from a single collection site in a small tributary of the upper Lualaba drainage in Lualaba province, Democratic Republic of Congo, formal conservation assessment has not yet followed. The known range is narrow by definition: a restricted collecting locality in the upper Lufupa River system, which is a modest drainage in a region of southeastern DRC that is undergoing increasing pressure from artisanal and small-scale mining activity — the Lualaba province and adjacent areas of the DRC's Copperbelt are heavily affected by copper and cobalt extraction, with associated drainage alteration, erosion, sedimentation, and chemical contamination of small watercourses.
Small-stream lampeye killifish of the Congo basin frequently have highly restricted natural distributions and show sharp range boundaries tied to individual stream systems or drainage divides. For a species known only from a small temporary stream in a single tributary, localised disturbance — stream diversion, seasonal mining run-off, habitat clearance — could have a disproportionate impact on the entire known population. Ongoing collection and population surveys across the upper Lualaba system would be needed to determine whether L. nitida occurs in additional drainages or is genuinely confined to the Lufupa system, and to provide the baseline data for a meaningful IUCN assessment. Until that work is done, its conservation standing remains unknown but its restricted known range warrants precautionary attention.