Taxonomy & naming
Apistogramma rupununi was described by the American ichthyologist Henry Weed Fowler in 1914, in his paper "Fishes from the Rupununi River, British Guiana" (Proceedings of the Academy of Natural Sciences of Philadelphia, vol. 66, p. 277, fig. 19). Fowler did not raise it as a full species but as a subspecies — Apistogramma ortmanni rupununi — a name that remains the species' principal synonym and the original combination carried by the Catalog of Fishes. It was later treated as a valid species in its own right, a status confirmed by Kullander in the 2003 Check List of the Freshwater Fishes of South and Central America and upheld by subsequent authors including Staeck (2003, 2017), Römer (2006) and Taphorn and colleagues (2022). The type locality is the Rupununi River, Guyana (roughly 2°–3°N, 50°20′W); the holotype is held at the Academy of Natural Sciences of Philadelphia (ANSP 39347) with a single paratype (ANSP 39348), and the type material was catalogued by Böhlke in 1984.
The genus name combines the Greek apisto (uncertain) and gramma (line, mark, or — in FishBase's gloss — graphic signal), a fitting tag for a genus whose species are separated on fine, often inconstant patterning and on variably developed, incomplete lateral lines. The specific epithet is a toponym, simply honoring the type river. The Catalog of Fishes places Apistogramma rupununi in subfamily Cichlinae, while FishBase files the genus under Geophaginae; either way it sits within the South American "eartheater" radiation rather than among the African cichlids. FishBase's auto-generated English label is "Two-spot Apistogramma," but this is a database descriptor rather than a name in real hobby use, and the species is traded — when it is traded at all — under its scientific name. It belongs to a small cluster of Guiana-Shield apistos that includes Apistogramma ortmanni, Apistogramma steindachneri and Apistogramma roraimae, and it is easily confused with the middle-Amazon Apistogramma hippolytae, which carries a noticeably larger caudal spot and flank blotch — a mix-up documented even among experienced keepers on apistogramma.com.
Morphology
This is, by apisto standards, a fairly large and plainly built fish. Reported sizes vary with how they are measured. FishBase lists a maximum of about 1.5 in standard length (snout to tail base) for males and roughly 2 in for females, while keepers describe it as one of the larger Apistogramma: the genus specialist Mike Wise puts males at up to about 3 in total length, well past true-miniature size. The discrepancy is mostly the difference between standard and total length plus the size of fully grown wild males; both pictures are consistent with a fish that finishes noticeably bigger than the average dwarf cichlid.
Coloration is understated. Males are not strongly colored — typically grayish to olive-tan with metallic turquoise spangling on the flanks and cheeks that flares under good conditions, a dark lateral band, and the dark caudal and mid-flank spots that give the fish its "two-spot" tag. The original description notes a brown body with a dark band running from the snout through the eye, a large spot on the caudal peduncle, a large spot mid-side, and a tendency to vertical barring, with a caudal fin intermediate between the rounded tail of Apistogramma ortmanni and the more truncate tail of its relatives. Females are the more striking sex when it counts: outside breeding they are cryptic and brownish, but a ripe female turns vivid lemon-yellow. The two spots, the relatively deep body and the comparatively large adult size are the practical cues that separate it from look-alikes such as Apistogramma hippolytae, where the caudal spot and flank patch are larger and bolder.
Habitat
Apistogramma rupununi is restricted to the Rupununi River basin in Guyana and the Rio Branco basin in the Brazilian state of Roraima. Both drainages belong to the broader Amazon system (the Branco is a major northern tributary), and they meet at one of South America's most remarkable hydrological features: the Rupununi Portal, a seasonally flooded savanna and wetland corridor where high water lets fishes pass between the Amazon and the Essequibo. The IUCN estimates the species' extent of occurrence at roughly 444,0 mi², so it is geographically widespread even if it is nowhere abundant.
Its habitats are the quieter, shallower edges of this savanna mosaic rather than the main river channel. Apistos of this region occupy leaf-littered margins of creeks, ponds and flooded savanna across clearwater and blackwater conditions; in-situ water is warm, soft, and acidic to near-neutral. FishBase gives a temperature range of about 72–86 °F for the species, and the wider literature on these savanna waters reports pH roughly in the 5–7 band. Like other dwarf cichlids it is a shallow-water, benthopelagic fish of the littoral margin — there is no documented depth range beyond the shallow (on the order of 0–10 ft) creek- and pond-edge habitat its biology implies, so any depth figure here is inferred from habitat rather than measured. The whole system runs on a predictable annual flood pulse that swells the savanna from roughly May through September, expanding habitat and dispersal routes before the dry season contracts them again.
Feeding
Like its congeners, Apistogramma rupununi is a small benthopelagic micropredator that forages over and just above the leaf litter and soft substrate. No dedicated diet study exists for the species, but its trophic position is well bracketed by the genus and by FishBase's estimate of a trophic level around 3.3: it takes small invertebrates — aquatic insect larvae, microcrustaceans and other meiofauna sifted from detritus — and is best described as omnivorous with a carnivorous lean, the same picture the Guyana fish checklist gives when it labels the species an omnivore. In the Rupununi, basal energy for fish communities shifts seasonally between aquatic algae and flood-pulse inputs of terrestrial and detrital carbon, and a litter-margin dwarf cichlid like this one slots in as a minor consumer of the invertebrates that process that material. As a small, short-lived, fast-maturing fish it is itself prey for the larger characins and pike cichlids (Crenicichla) that share its leaf-litter and savanna-pond habitats.
Mating
Apistogramma rupununi follows the courtship pattern of its genus rather than anything documented uniquely for the species. Pairs — or, in roomier quarters, a harem of one male to several females — form around a small cavity, and the clearest behavioral signal is the female's color change: the cryptic brown breeding-ready female flushes bright lemon-yellow as she takes up station over a chosen site, a transformation FishBase notes explicitly for this species. The male holds the larger surrounding territory and courts and defends, while the female focuses on the cavity itself. Reports from the handful of keepers who have encountered the fish describe it as territorial but not exceptionally pugnacious for its size — it will claim a patch and chase intruders off it, yet is restrained enough to hold its own alongside other dwarf cichlids without the relentless aggression of some apistos. Because males run larger than typical apistos and hold real territories, pairs need more floor space than the genus average to pair off without one fish bullying the other.
Breeding
Apistogramma rupununi is a substrate-brooding cave spawner, the standard Apistogramma reproductive mode and quite unlike the maternal mouthbrooding of the African rift-lake cichlids. The female lays her clutch on the ceiling or wall of a small cavity — a hollow under wood, a crevice, a snail shell — and tends it there; FishBase records a clutch of about 200 eggs for this species, consistent with the genus, where clutches run from roughly 40 to a couple of hundred eggs. Parental care is strongly female-biased and follows the harem-cave template: the female guards and fans the eggs and shepherds the wriggler and free-swimming fry through the leaf litter, while the male patrols and defends the larger territory against rivals. Mike Wise, who kept the species in the 1990s, reports that it is "not really difficult to reproduce" in slightly acidic, moderately soft water — the same conditions its wild habitat implies. The fast-maturing fry grow on without special difficulty once past the early stages; the species' high resilience (a population doubling time under about 15 months, per FishBase) reflects exactly this quick, prolific cave-brooding life history.
In the aquarium
Apistogramma rupununi is a genuinely rare fish in the hobby. It is not commercially collected in any meaningful volume — neither Guyana nor the upper Rio Branco is a hotspot for ornamental exporters — and most keepers who have worked with it obtained specimens through specialist importers or private breeders. If you do find it, the experience is closer to the mid-tier Apistogramma than to the easiest species: it is not a fish for beginners, but it does not demand the near-distilled blackwater that the most exacting Peruvian apistos require. Generalizing from closely related Guiana-shield species is necessary here, since documented keeper accounts are thin.
A single pair can be maintained in a 60-liter (roughly 24-inch / 23.5 in) footprint tank, but because males grow notably large for the genus — up to around 3 in total length — and hold real territories, a harem arrangement of one male to two or three females works better in a tank of 20–30 US gal with a long footprint (35.5–39.5 in). Water conditions should stay within the parameters the wild habitat implies: 75–82 °F is a practical keeper range within the wild 72–86 °F band, pH 5.5–6.8, and soft to moderately soft water (no harder than about 8 dGH). The species tolerates near-neutral conditions better than many western-Amazon apistos — the Rupununi savannas span a range from acidic blackwater to near-neutral clearwater — so hard tap water is the one thing to genuinely avoid rather than a chase for ultra-soft RO at a specific pH.
Substrate should be fine sand, not gravel, with a generous layer of dried leaf litter (Indian almond or equivalent) over at least part of the floor. Flat stones, short lengths of pipe, coconut-shell halves, or small clay caves provide the spawning cavities the species needs; the female will inspect and choose, so offering more options than there are females works well. Driftwood and low-light plants (Java fern, Anubias, floating plants) complete the biotope feel and help break sight lines — reducing stress and male-on-female aggression. Subdued lighting is appreciated. Filtration should be gentle; the slow, leaf-littered creek margins this fish comes from have minimal current, and a powerhead blasting the tank will stress it.
For tankmates, small peaceful characins from Guyana make logical companions — hatchetfishes, small pencil-fishes, or diminutive tetras — and serve as dither fish that signal to the cichlids the tank is safe. Avoid other bottom-dwelling cichlids, particularly other Apistogramma, unless the tank is large enough for clear territorial separation. Larger, boisterous tetras and any aggressive fish will harass a ripe, brooding female. Other dwarf cichlids such as Dicrossus are sometimes kept alongside Apistogramma in larger setups, but the male rupununi's size and aggression capacity make this a judgment call rather than a default recommendation.
Sexing is straightforward once the fish are of breeding size: males are noticeably larger, drabber (grey-olive with turquoise spangling under good conditions), and develop elongated dorsal and pelvic-fin rays; females stay smaller and turn the vivid lemon-yellow that announces both readiness to breed and active brood care. Cave-spawning proceeds as with the genus broadly — female deposits eggs on the cavity ceiling, fans and guards them alone, and shepherds free-swimming fry through the litter while the male defends the outer perimeter. Mike Wise, who bred the species in the 1990s, described reproduction as not really difficult in slightly acidic, moderately soft water, and FishBase records a clutch of around 200 eggs. The most common keeper mistake, consistent with the genus, is placing a pair in too small a footprint: the male needs room to establish a territory that he treats as genuinely his without constantly pressuring the female.
Conservation
Apistogramma rupununi is assessed as Least Concern on the IUCN Red List (assessment by Renata Guimarães Frederico; assessed 29 October 2020, carried in the 2025 update). The reasoning is straightforward: despite very little being known about the species, its wide range across the Branco and Rupununi basins (an extent of occurrence of roughly 444,0 mi²) keeps it well clear of the thresholds for a threatened category. The population trend is listed as unknown, and the assessment notes the fish does not appear to be common or abundant. No specific threats are recorded against it. It is used as an ornamental fish in national and international trade, but at a low level — consistent with the hobby's experience that the species is only rarely collected and exported, because neither Guyana nor the upper Rio Branco is a hotspot for commercial collectors. It also appears in Brazil's national Red Book of threatened fauna (ICMBio 2018) without being flagged as at risk.
That individual security should not be mistaken for an untouched habitat. The Rupununi savannas and wetlands — the corridor this fish depends on — sit under real and growing pressure from gold and diamond mining, which brings sedimentation and mercury contamination, and much of the savanna still lacks formal protection. Across the genus, narrow-range apistos are the ones genuinely exposed to forest clearance and dam construction; Apistogramma rupununi, being widespread and tolerant of a range of savanna water types, is comparatively buffered. The honest summary is the one the data support: the species itself is currently Least Concern and faces no documented collapse, while the flood-pulse wetland system that sustains it is a globally significant but only partly protected landscape worth watching.