Taxonomy & naming
Apistogramma cinilabra was formally described in 2011 by Uwe Römer and co-authors (Duponchelle, Vela Díaz, García Dávila, Sirvas, Díaz Catchay and Renno) in the journal Vertebrate Zoology (61(1):3–23), from a series of 35 specimens. The holotype, an adult male, is held at the Museo de Historia Natural in Lima. The species belongs to the family Cichlidae, subfamily Geophaginae, and the describers placed it explicitly as "a representative of the Apistogramma eunotus complex within the Apistogramma regani lineage" — a placement echoed by Mike Wise's widely used species-group framework on apistogramma.com and by TomC's apisto-sites profile (regani group / eunotus complex). The authors flagged one complication: breeding females show a double caudal-peduncle spot more typical of other regional groups, which leaves the fine-scale affinities open.
The genus name joins the Greek apisto (uncertain) to gramma (a marking or graphic signal), traditionally read as a nod to the variably developed, often incomplete lateral line. The epithet is the more vivid half. Cinilabra is a compound of the Latin cinis/cineris (ashes) and its derived adjective cinereus (grey) with labrum (lip) — "ash-grey-lipped" — for the pale lip colour that displaying males show. Before it had a Latin name, the fish circulated among Apistogramma enthusiasts under several provisional trade labels, most often Apistogramma sp. "Schwarzbrust" (black-breast) and variants such as "Roterpunkt"/"Rotpunkt" (red spot); it also carries the informal hobby code A 80. FishBase attaches the label "redbellied dwarf cichlid," but that is an aggregator-coined name rather than an established trade or hobby one — collectors and keepers use the provisional labels or the scientific name — so it is noted here in prose rather than elevated to a common name.
Morphology
This is a small fish even by Apistogramma standards: the largest measured specimen reached about 2 in standard length, with females smaller still. The body is notably deep and short — the describers singled out an "exceptionally short caudal peduncle" and a "disproportionately deep body" — giving it a stockier outline than many of its slimmer congeners. Fin counts run to roughly 14–16 dorsal spines and 6–8 dorsal soft rays, with three anal spines and 6–8 anal soft rays.
Mature males carry the species' signature look: a strikingly red base to the pectoral fin and red spots scattered across the chest, abdomen, gill covers and cheeks, all set against the creamy-white to light ash-grey lips that surface when the fish is in an aggressive or courtship mood. That full combination — red pectoral base, red chest spots, ash-grey lips, the short caudal peduncle and the deep body — is what separates Apistogramma cinilabra from every other member of the genus. Colour is strongly mood-dependent and varies markedly from one male to the next; the authors suggested this polymorphism may be tied to female mate choice, a theme running through recent Apistogramma research. The species is sexually dimorphic in both size and colour: males are larger and far more vivid, while females in breeding dress turn the genus-typical yellow and show a paired spot on the caudal peduncle. It is that double spot, more than the red trim, that has kept the lineage placement under discussion.
Habitat
Apistogramma cinilabra is endemic to the Peruvian Amazon, in the Departamento Loreto, within the wider catchment of the Río Itaya. The type locality is a small forest lake — a cocha — roughly 50 mi south of Iquitos, near 04°24′S, 73°35′W. The describers reported it from a single pond of less than a hectare, set in a forested depression with no inflowing or outflowing streams, which made it look like an extreme single-site endemic. Field reports complicate that picture: Mike Wise and Tom Christoffersen, who reached the type locality in 2008, also took the fish from a stream farther south and place its broader range loosely between Iquitos and Nauta. Wise's own reading is that the species "is not restricted to this one lake," yet still has a genuinely restricted distribution and should be considered vulnerable to habitat destruction.
The habitat is classic acidic blackwater. The type pond is shallow — depth on the order of 3–10 ft — and remarkably steady, with the describers reporting seasonal level swings of only about 8 in, unusual for an Amazon water body that does without the annual flood pulse. The bottom is carpeted in leaf litter, twigs, fallen wood and fine brown detritus, dotted with algae and drifting moss-like vegetation. The water is very acidic and ion-poor: a pH of about 4.1 was recorded at the type locality, and Christoffersen elsewhere logged pH around 4.44, conductivity near 31 µS/cm, and temperatures of about 84–86 °F (84–86 °F). FishBase summarises the tolerance as pH 4.1 and up, depth 3–10 ft, and 79–86 °F — though, given how little fieldwork exists, those are best read as a handful of point measurements rather than a well-mapped envelope.
Feeding
No dedicated feeding study has been published for Apistogramma cinilabra, so its diet is inferred from its body plan, its habitat, and the well-documented habits of the genus. Like other Apistogramma, it is a small benthopelagic micro-predator of the leaf-litter zone, sifting and picking at the substrate for aquatic insect larvae, microcrustaceans and other small invertebrates; FishBase places it at an estimated trophic level around 3.4. In a tannin-stained pond floored with decaying leaves and wood, that litter layer is both larder and cover — the same detritus that acidifies and darkens the water also feeds the invertebrate community the cichlids hunt.
Its ecological role is that of a small, territorial bottom-dweller in a low-diversity blackwater system. The describers recorded only a handful of other fish in the type pond and, tellingly, no other Apistogramma — so within its tiny world it is the resident dwarf cichlid rather than one of several competing congeners, a contrast to the species-rich, multi-Apistogramma streams common elsewhere in Loreto.
Mating
Apistogramma cinilabra is a harem-forming, polygamous cichlid, the dominant pattern in the genus: a single alpha male holds a larger territory across which several females keep smaller breeding territories, each of which she defends and within which she spawns. Christoffersen, who has kept and bred wild fish, describes the alpha male setting up such a territory while smaller, subordinate males simply hide among floating vegetation. The species reads as comparatively mild-tempered for a cichlid, with most of the friction coming from the females rather than from male-on-male combat.
Male display is where the fish earns its name. In aggression and courtship the lips pale to ash-grey while the red chest and pectoral markings intensify, and the considerable variation in pattern from male to male hints, in the authors' reading, at sexual selection through female choice. In the aquarium this courtship plays out in a small, heavily structured tank — leaf litter, wood, caves and floating plants such as Ceratopteris to break sightlines and give subordinate fish refuge — which lets one male and several females hold their respective territories without the harem collapsing into constant fighting.
Breeding
Within each female's territory, Apistogramma cinilabra is a cave (substrate) spawner: the female deposits and tends her clutch in a sheltered crevice or cavity and guards the eggs and resulting fry, while the male defends the wider territory and visits the harem's several breeding sites. The describers noted one behavioural oddity — both sexes are unusually aggressive in defending fry, where in many Apistogramma the female alone does the close guarding. Keepers add a further wrinkle: where several females raise broods at once, they routinely raid one another's fry, so wigglers drift between guardians. No precise wild clutch count has been published, so fecundity is best left as the genus-typical few dozen to ~150 eggs rather than a measured figure.
Like every Apistogramma examined to date, the species shows temperature-dependent sex determination: the temperature a brood experiences during a sensitive early window biases its eventual sex ratio, with warmer water skewing broods toward males. Breeders of the genus generally aim for the mid-20s Celsius (around 77–79 °F / 77–79 °F) to get balanced clutches — anecdotal, cross-species hobby lore rather than a measurement specific to this fish, but consistent with the published genus-wide pattern. In practice the species breeds without exotic water; Christoffersen reports it spawning across a wide range, roughly pH 4–7. Even so, its wild home is so soft, acidic and chemically stable that it rewards steady conditions over chased ones, and Römer noted it reacting badly to swings in water chemistry — plausibly because its flood-free pond spares it the seasonal shifts most Apistogramma endure. This is not a beginner's first dwarf cichlid; it is a species for a keeper willing to commit to stable blackwater and careful, conservation-minded breeding.
In the aquarium
Formally described only in 2011, Apistogramma cinilabra has never been a common aquarium fish; most online accounts are brief, and some keepers advertising it may in fact hold misidentified congeners. Treat any husbandry advice as largely inferred from the eunotus complex and the broader genus, topped up with the thin but credible reports of the few keepers — notably Tom Christoffersen — who have demonstrably held and bred wild-caught or F1 stock. With that caveat stated plainly, the fish does not seem to demand anything beyond the blackwater conditions of its wild home.
Tank: a single pair can live in a well-decorated 15–20 US gal tank (about a 60 × 15.5 in footprint), but a harem — one male with two or three females — suits the species' polygamous structure better and eases pressure on any one female; for that, a 25–30 US gal tank (31.5–39.5 in long) gives each female room and sightlines broken by wood, root tangles and floating plants such as Ceratopteris or Salvinia, which also shelter ousted females and subordinate males. The substrate should be soft, fine and dark — sand over inert material, dressed with patches of dried leaf litter (Indian almond, oak or beech) — and each female's territory needs at least one spawning cave, whether half a coconut shell, a small clay pot on its side, or a tight crevice between wood.
Water: the one known natural site is among the most acidic measured in the genus (around pH 4.1, conductivity 31 µS/cm, 84–86 °F), but a practical keeper's target of pH 5.0–6.5, conductivity under 100 µS/cm and 79–82 °F is achievable and consistent with the facts here. Christoffersen has bred it up to pH 7, so the fish is not fragile outside extreme acidity, yet the describers saw it react poorly to sudden chemistry swings — no surprise for a flood-free forest pond, one of the most stable habitats in lowland Amazonia. Soft, aged reverse-osmosis or rain water conditioned with leaf litter or alder cones is the sensible route; because the type pond has no inflow or outflow, keep currents gentle, with sponge filtration, weekly matched water changes, and no sudden temperature drop.
Tankmates: sexing is easy in adults — males are larger, with the red pectoral-base flash, red chest markings and ash-grey display lips, while females are smaller, plainer and switch to breeding yellow. Pair the cichlids with small, peaceful, upper-column dither fish that won't contest the bottom, such as Nannostomus pencilfish or ember tetras, which seem to settle them; avoid other bottom-dwellers that would fight over the females' territories. Keeping this species alongside other Apistogramma is a mistake unless the tank is very large and the species occupy distinct micro-habitats — mixing congeners in a standard tank usually means chronic stress or hybridisation risk.
Common mistakes: the recurring errors are holding the temperature too high for too long, which through temperature-dependent sex determination quietly biases broods toward males and ruins the line; making large water changes with hard tap water; and overcrowding the female territories until constant aggression stops the females holding condition. Apistogramma cinilabra sits firmly in the experienced-keeper bracket — not because it is physiologically delicate, but because its rarity, its Vulnerable status, and the real demands of stable blackwater and brood-temperature control make it a poor casual buy. Anyone who does obtain it takes on a genuine conservation responsibility, and holding a healthy line with balanced sex ratios is the most useful thing the hobby can do for the species.
Conservation
Apistogramma cinilabra is assessed by the IUCN as Vulnerable (VU, criterion D2), in an assessment dated 25 April 2014 by Chuctaya, Correa and Ortega of the natural history museum in Lima (UNMSM-MHN). The D2 listing reflects not a documented decline but a very restricted range — essentially a single, or near-single, locality — that leaves the species one plausible disturbance away from a much worse status. The describers were blunt about the threat: the land and forest around the only confirmed site were, at the time of description, being offered for sale for timber-felling. CITES and CMS list the species as Not Evaluated, and direct collection for the aquarium trade appears minor — this is a habitat-and-isolation story, not an over-collection one.
The regional context sharpens the concern. The forest pools and streams around Iquitos sit on a low rise, the Iquitos paleo-arch, that limits the annual flood connectivity typical of the Amazon and so isolates small water bodies — the very mechanism that drives the area's high Apistogramma endemism and the reason narrow-range species like this one exist at all. Beninde, Römer and colleagues (2020) showed that small-scale deforestation around the fast-growing city sharply raises stream and pond temperatures where the canopy is removed, and that, stripped of leaf-fall, the characteristic low pH and conductivity erode too. Because every Apistogramma studied shows temperature-dependent sex determination, that warming is not a vague stress but a specific demographic threat: it can skew wild broods toward males and unbalance populations even without outright habitat loss. For a fish confined to one shaded blackwater pond, the loss of surrounding forest is therefore doubly dangerous. Set against the wider Neotropical cichlid fauna catalogued by Kullander (2003) — most of whose Apistogramma are unevaluated or of lesser concern and face ornamental collection and habitat change rather than collapse — Apistogramma cinilabra is an outlier, a genuinely narrow-range endemic for which the standard regional pressures of deforestation and warming translate into an unusually direct extinction risk.