Taxonomy & naming
Lina M. Mesa Salazar and Carlos A. Lasso described Apistogramma pedunculata in 2011, in the third part of their revision of the genus Apistogramma (Regan, 1913) in the río Orinoco basin ('Revisión del género Apistogramma Regan, 1913 (Perciformes, Cichlidae) en la cuenca del río Orinoco'). It was placed directly in Apistogramma, so the original combination and the current valid name are one and the same. Eschmeyer's Catalog of Fishes lists it as valid and endemic to the Orinoco basin of Venezuela, and the holotype (MHNLS 16719) is held at the Museo de Historia Natural La Salle in Caracas.
Before that description the species had a long provisional life. Material now referred to Apistogramma pedunculata had earlier been called 'Apistogramma cf. hoignei' (Kullander), and it circulated among hobbyists and in Staeck's writing as 'Apistogramma sp. Rio Caura' or 'Apistogramma sp. Caura.' Mike Wise, whose lineage framework is the hobby's standard reference, places it in the hoignei lineage, close to its namesake Apistogramma hoignei, with which it shares the Caura drainage. The cleanest way to tell the two apart is the proportionally longer caudal peduncle that gives Apistogramma pedunculata its name.
Morphology
Apistogramma pedunculata is a small dwarf cichlid. The original description records the largest type specimen at 2 in standard length (about 2 in, snout to tail base), squarely within the usual band for the genus; FishBase carries no separately published maximum length, and hobby sources round the figure to roughly 1.5–2 in. The one diagnostic feature the literature and the hobby keep returning to is the one the name records: a proportionally long caudal peduncle, the narrow stalk in front of the tail fin. Otherwise it is understated — a generally plain, beige-to-tan ground colour rather than the bold finnage of the showier members of the genus, in keeping with its place beside the comparatively subdued Apistogramma hoignei.
Quantified detail on colour, fin counts, and sexual dimorphism sits in the original 2011 description and is not well reproduced in open secondary sources. As is the rule across Apistogramma, males can be expected to be the larger and longer-finned sex, but the specific dimorphic markers of Apistogramma pedunculata are not documented in the public material consulted here, so they are left unstated rather than inferred.
Habitat
Apistogramma pedunculata is endemic to the Venezuelan Orinoco basin, documented from the middle río Cataniapo and the río Caura, both right-bank tributaries draining the Guiana Shield. The type locality is precise: río Cataniapo at salto Nievas, 5°38'17"N, 67°06'56"W, Estado Amazonas, Venezuela — and the curated occurrence point for this species is that type locality, best read as approximate to within the locality rather than a GPS fix on a single fish. FishBase files it broadly as a tropical freshwater species of the río Orinoco basin, with no published depth, temperature, or pH figures attached.
The IUCN assessment, drawing on Mesa and Lasso's own fieldwork, is more specific about the water: rivers and floodplain lakes of highly acidic, ion-poor blackwater, measured at pH 5.61–5.82 and conductivity of just 12–20 µS/cm — the soft, tannin-stained chemistry typical of the white-sand Guiana Shield — where the fish reaches high local densities in small patches along the littoral (shore) zone. The wider biotope follows the regional norm and hobby reports: shallow, slow, structurally complex stream margins over sand and leaf litter. Two of the fact-strip figures need reading with care. No published depth range exists — neither FishBase nor the IUCN assessment (whose depth-limit fields are left blank) gives one — so the 0–7 ft band stands for the documented shallow littoral / river-margin zone where densities run high, not a measured maximum. The often-quoted 75–82 °F is likewise a husbandry recommendation, not an in-situ measurement.
Feeding
No wild dietary study of Apistogramma pedunculata has been published. FishBase estimates a trophic level of about 3.3 from the size and relationships of its closest relatives rather than from gut contents, placing it among the small carnivores. In practice, dwarf cichlids of this genus are micro-predators that pick small invertebrates — insect larvae, microcrustaceans, and other meiofauna — from the substrate and leaf litter, often by taking mouthfuls of fine sand and sieving the edible fraction through the gills. That is the reasonable expectation for Apistogramma pedunculata given its lineage and habitat, but it is an inference from the genus, not a measured fact for this species.
Mating
The mating system of Apistogramma pedunculata has not been described. Across the genus, Apistogramma are typically polygynous cave spawners: a dominant male holds a territory that overlaps the smaller territories of several females, each female defending her own spawning cave — though some species run closer to monogamy. Which pattern Apistogramma pedunculata follows is not documented in the public sources consulted, and the original description deals in morphology rather than behaviour. No courtship, pair-formation, or territoriality observations specific to this fish are on record here.
Breeding
Breeding of Apistogramma pedunculata has not been documented, in the wild or in aquaria, in the sources consulted. By strong analogy with the rest of the genus it is expected to be a female-tending cave spawner: the female lays a small clutch — congeners typically produce on the order of 40–200 eggs per spawn — on the roof or wall of a sheltered cavity, then tends and fans the eggs and larvae while the male guards the wider territory. No clutch size, spawning trigger, or fry-development data specific to Apistogramma pedunculata are available, and the fish is too rare in the trade for a reliable body of aquarist breeding reports to have built up. Everything here beyond the bare 'no records' statement is flagged as inference from the genus.
In the aquarium
Apistogramma pedunculata is an extreme rarity in the hobby. It was circulating under provisional names — 'Apistogramma sp. Caura,' 'Apistogramma cf. hoignei' — even before its 2013 formal description, and it has not crossed into regular trade since. Anyone keeping it today almost certainly got it through specialist contacts rather than a shop, and documented aquarium experience with the species is negligible. The guidance below is honest about that: where species-specific information does not exist, it leans on the closely related hoignei group and on genus-level Apistogramma practice, and says so.
Water: this is the hard part. Wild fish came from Guiana-Shield blackwater at pH 5.61–5.82 and conductivity of just 12–20 µS/cm — some of the softest, most acidic water in cichlid-keeping. Tap water that is merely 'soft and acidic' by temperate standards will likely fall short for conditioning or breeding; the realistic target is reverse-osmosis water re-mineralized with a blackwater peat extract to hit those same pH and conductivity values. Temperature can follow the general Orinoco-blackwater Apistogramma band of 75–82 °F, and stability matters more than any exact point within it — sudden swings in pH or conductivity stress fish acclimatized to stable, ion-poor water and can trigger disease.
Tank: 15–20 US gal suits a single pair or a small harem. Fine, light silica sand under a covering of dried oak or Indian almond leaves recreates the leaf-litter floor the fish picks over, and several small ceramic caves, coconut-shell halves, or terracotta pots on their sides are essential — Apistogramma pedunculata almost certainly spawns inside enclosed cavities like the rest of the genus, and females use caves as retreats even outside breeding. Low flow, dim tannin-filtered light, and dense plantings or driftwood along the sides and back finish the setup; vigorous filtration that stirs strong current or dilutes the acidification is counterproductive.
Tankmates: choose for the chemistry first. Other Guiana-Shield or Orinoco-basin fish that tolerate very soft, acidic water work in principle — small pencilfish (Nannostomus), hatchetfish, or similarly acid-tolerant tetras in the mid-to-upper column. Avoid fast, nippy schoolers and anything that competes for bottom space; the female's territory around the cave is small and she will be harassed by bottom-dwelling rivals. For breeding or study, a species-only tank with no dither fish at all is safest. Males are territorial toward each other, so keep only one per tank unless the footprint can hold two non-overlapping female territories, one around each male.
Common mistakes and sexing: sexing and breeding notes must lean on the genus. Males are expected to be larger and longer-finned; females of the hoignei group show a yellow lateral blotch and a darkened lateral stripe when brooding. A female that has claimed a cave and begun darkening warrants removing the male in a small tank, since the genus-typical female care means she will defend the clutch and larvae aggressively while he may harass her. Hoignei-lineage congeners lay modest clutches — likely in the lower range of the genus, around 40–80 eggs — with fry free-swimming in roughly a week to ten days at typical Orinoco temperatures. Rear the fry in matching chemistry from the start to spare them an osmotic shock. The narrow chemistry window, the scarcity of captive-bred stock, and the near-absence of keeper records make this a fish for experienced Apistogramma specialists rather than a beginner.
Conservation
The IUCN Red List assesses Apistogramma pedunculata as Near Threatened (NT) under criterion B2b(iii), assessed 7 August 2019 by Gabriela Echevarría (reviewed by C. Sayer; published 2019). The category reflects a small, severely disjunct range. The extent of occurrence is fairly wide — about 41,114 mi² — but the area actually occupied is tiny, an estimated 22 mi², and it is split between just two rivers: the Cataniapo in Amazonas state and the Caura in Bolívar state. They lie far enough apart that the assessment judged any natural rescue of one subpopulation by the other effectively impossible. A continuing decline in habitat quality is inferred in the lower Caura, where the assessment flags log extraction and gold-mining pollution — three illegal gold mines were documented within the species' range there — as ongoing pressures fragmenting and degrading the habitat. The Caura subpopulation does fall within a national park, and roughly 41–50% of the overall population is estimated to have some protected-area coverage, but the assessment still calls for better on-the-ground protection at the actual occurrence sites. There is no CITES listing, and whether the fish enters the ornamental trade is, per the assessors, unknown.