Taxonomy & naming
The species was described by the American ichthyologists John Treadwell Nichols and Francesca R. La Monte in 1931, as Lamprologus finalimus, in the American Museum Novitates (number 478), from a single specimen collected at Uvira in the far north of Lake Tanganyika, in what is now the Democratic Republic of the Congo. That holotype — AMNH 9689 — remains the only specimen on which the species is based; it is, in the literal sense, unique. The Latin epithet finalimus means 'at the boundary' or 'outermost', an apt name for a fish from the extreme northern end of the lake. Maréchal and Poll retained it as a valid Lamprologus in the CLOFFA check-list of African freshwater fishes (1991), and Konings (2015, 2019) listed it as ''Lamprologus'' finalimus, again reflecting the unsettled generic limits of the small Tanganyikan lamprologines. Eschmeyer's Catalog of Fishes currently recognises it as Neolamprologus finalimus (Nichols & La Monte 1931); FishBase still files the same fish under the older combination Lamprologus finalimus. The shifting genus is not a sign of new information about the animal — there is essentially none beyond the original description — but of the broader reorganisation of the lamprologine genera. This account uses the Catalog of Fishes' current valid name, Neolamprologus finalimus.
Morphology
What is known of the fish's appearance comes entirely from the 1931 description of the single holotype. It is a small lamprologine, with a maximum recorded length of about 2 in total length — among the smaller members of the genus. Beyond the basic body plan of a slender, small-scaled lamprologine cichlid, detailed and reliable colour and meristic data are thin, because the species has never been re-collected and the original account rests on one preserved specimen. No photographs of living Neolamprologus finalimus exist, and FishBase carries no image. Any description of its colour pattern in life, or of sexual dimorphism, would be speculation; the honest statement is that the species' morphology is documented only at the level of a single, century-old type specimen, and that a modern redescription based on fresh material has never been possible.
Habitat
Neolamprologus finalimus is endemic to Lake Tanganyika and, on the only evidence available, known solely from its type locality at Uvira, at the extreme northern end of the lake near the modern DRC–Burundi border — placing it in the Lake Tanganyika freshwater ecoregion (FEOW 521). FishBase records it simply as endemic to the lake and known only from Uvira. No micro-habitat data (substrate, depth, associated species) accompany the original collection in any usable form, so its preferred habitat within the lake is unknown. By analogy with other small northern lamprologines it would be expected somewhere in the littoral zone — over rock, sand or shell beds — in the warm, hard, strongly alkaline water characteristic of Tanganyika (broadly 75–81 °F, pH around 8–9, high carbonate hardness). But this is inference, not observation. The species may genuinely be rare and localised, or it may simply be under-sampled, or — a possibility that cannot be excluded for a one-specimen taxon — it could ultimately prove to be a variant or junior synonym of a better-known northern lamprologine.
Feeding
There is no dietary information for Neolamprologus finalimus. No gut-content study has been done, no field feeding observations exist, and FishBase lists no food items; its model-estimated trophic level of about 3.4 is derived purely from its size and from the trophic levels of its closest relatives, not from any direct evidence. By analogy with the small lamprologines of the lake's northern littoral, it would most plausibly be a micro-carnivore, picking small invertebrates, crustaceans and zooplankton from the substrate and the lower water column. That is the reasonable default for a fish of its size and lineage, but for this species specifically it remains entirely unverified.
Mating
The mating system of Neolamprologus finalimus is unknown. The fish has never been observed alive in the wild or in captivity, so there are no data on courtship, pair formation, territoriality or whether it follows the harem-based, shell-associated pattern common among the small lamprologines or the pair-bonding, substrate-spawning pattern of others in the group. Any account of its reproductive behaviour would be pure extrapolation from relatives. Given the small size of the holotype, a shell- or crevice-associated mode would be plausible, but no part of this can be stated as fact. This is one of those Tanganyikan cichlids where the responsible position is simply to record that nothing is known.
Breeding
Nothing is documented about the breeding of Neolamprologus finalimus. Like all cichlids it is presumed to be a substrate-guarding brooder with biparental or maternal care of eggs and fry, since that is universal in the family, but no clutch size, spawning site, egg description, developmental data or parental-care observations exist for the species. Whether it spawns in shells, in rock crevices, or on open substrate is unknown. The complete absence of breeding information is a direct consequence of the species being known from a single preserved specimen collected nearly a century ago and never re-found; until living animals are located and studied, the breeding biology will remain a blank.
In the aquarium
Neolamprologus finalimus has, to all appearances, never been kept in the aquarium. It is not present in the ornamental trade, there are no hobbyist accounts of maintaining or breeding it, and no aquarium-strain populations exist. This is unsurprising for a fish known only from its holotype and never reliably collected since 1931. Any practical care recommendations would simply be the generic protocol for small Tanganyikan lamprologines — a hard, alkaline, warm tank (about 75–81 °F, pH roughly 8–9, high carbonate hardness), a sand substrate with shells and rockwork, small live and frozen foods — but it must be stated plainly that these are extrapolations from related species and not based on any experience with Neolamprologus finalimus itself. For the foreseeable future this is a 'museum' species rather than an aquarium one; the priority is rediscovery in the field, not husbandry.
Conservation
The IUCN Red List assesses Neolamprologus finalimus as Data Deficient (assessed 11 March 2025; Red List 2025-2). The Data Deficient category is exactly appropriate: the species is known from a single specimen from one locality, has not been reliably recorded in nearly a century, and there are no data on its population, distribution, habitat requirements or even its continued existence as a distinct, extant taxon. It is impossible to say whether it is genuinely rare, merely overlooked, or invalid. Such a one-locality, one-specimen fish would, if real and extant, be highly vulnerable to any disturbance of the northern Tanganyikan littoral — the area around Uvira is subject to the pollution, sedimentation and fishing pressure typical of the lake's populated northern shore — but no threat can be meaningfully assessed without basic field data. The species carries no CITES listing. The clear priority flagged by its Data Deficient status is fundamental: targeted survey of the Uvira area and the northern lake to determine whether Neolamprologus finalimus still exists and is a valid species before any extinction-risk evaluation is possible.