Taxonomy & naming
Tahuantinsuyoa chipi was described by the Swedish ichthyologist Sven O. Kullander in 1991, in a dedicated paper in the journal Cybium (volume 15, number 1, pages 3–13) titled 'Tahuantinsuyoa chipi, a new species of cichlid fish from the Rio Pachitea drainage in Peru.' The holotype (Royal Ontario Museum, ROM 58725) was taken from pools of an unnamed creek close to the lower Río Llullapichis, 1.8 kilometres east of the Panguana research station in the Huánuco Department of central Peru, with paratypes distributed among the ROM, the Muséum d'histoire naturelle in Geneva (MHNG) and the Swedish Museum of Natural History (NRM). The species' ZooBank registration is 16AFA282-07E4-4D02-91E1-09EAB254CFA0.
The genus Tahuantinsuyoa was itself erected by Kullander only five years earlier, in his 1986 monograph 'Cichlid fishes of the Amazon River drainage of Peru,' to hold the single species then known, Tahuantinsuyoa macantzatza. Tahuantinsuyoa chipi became the second and, to date, last member of the genus. The two are close relatives — the species epithet explicitly flags that kinship (see Etymology) — and Kullander diagnosed chipi as a smaller, distinct form on meristic and colour-pattern grounds. Within the family the genus sits in the subfamily Cichlinae, tribe Cichlasomatini, a largely Amazonian assemblage of small-to-medium 'acara'-type cichlids; the Catalog of Fishes and FishBase place it there, and the molecular phylogeny of the Cichlasomatini by Musilová and colleagues, together with the broader Cichlinae analysis of López-Fernández et al. (2010), has consistently recovered Tahuantinsuyoa among the cichlasomatine cichlids near genera such as Bujurquina and Aequidens. No synonyms are recognized; the name has been treated as valid by every subsequent author, including Chang & Ortega (1995) and Kullander's own 2003 checklist treatment in Reis, Kullander & Ferraris.
Morphology
Tahuantinsuyoa chipi is a small cichlid: FishBase records a maximum of 3 in standard length (the snout-to-tail-base measurement), and the Catalog of Fishes-linked checklist material cites figures around 2.5 in SL for typical specimens, making it appreciably smaller than its congener Tahuantinsuyoa macantzatza, which reaches roughly 4.5 in total length. The body is the moderately deep, laterally compressed 'acara' form characteristic of the Cichlasomatini, with a rounded snout and a continuous dorsal fin.
Detailed colour notes for chipi come chiefly from Kullander's original description and from the few field photographs of freshly collected fish, which show a tan to greyish-brown ground broken by a series of vertical bars along the flank and a dark mid-lateral blotch or spot — the patterning typical of the genus and of small cichlasomatines generally. Like its sister species, which in life can flush with the iridescent blue-green flecking that earned the 'Inca stone' name, chipi carries scattered light spangling on the body and fins, most evident in conditioned adults. Because so few specimens have been examined alive, the species' full breeding coloration is poorly documented.
Sexual dimorphism is modest and, for chipi specifically, only lightly recorded; by analogy with Tahuantinsuyoa macantzatza and other cichlasomatines, males are expected to grow somewhat larger and to develop slightly more produced (pointed) dorsal- and anal-fin tips, while ripe females are rounder-bodied. The sexes are not strongly dichromatic, and reliable in-tank sexing generally depends on venting or on observing behaviour at spawning rather than on colour alone.
Habitat
Tahuantinsuyoa chipi is a narrow-range endemic of the upper Amazon basin in central Peru, confined to the Pachitea river system — itself a major tributary of the Ucayali — on the eastern flank of the Andes. The IUCN range assessment records it from the Pachitea proper and its components the Palcazu and Pichis rivers, plus the Llullapichis at the type locality, at altitudes between roughly 160 and 300 metres above sea level. The Catalog of Fishes notes the broader Amazon-basin distribution as Ecuador and Peru, but the verified, mapped occurrences all fall within this compact Peruvian foothill area; the extent of occurrence is estimated at only about 6,500 square kilometres across four known locations.
These are clearwater habitats rather than the blackwater or whitewater extremes of the lowland Amazon: the IUCN ecology note describes the species as living in clear rivers and streams, and the type series came from quiet pools of a small forest creek. As a foothill clearwater fish it occupies warm, relatively well-oxygenated running water with the soft, near-neutral chemistry typical of Andean-piedmont streams. No comprehensive in-situ water-chemistry dataset has been published for chipi itself; its close relative Tahuantinsuyoa macantzatza has been kept successfully across pH about 6.3–7.7, very soft water (around 2–2.5 °dH) and 77–82 °F, and these figures are the best available proxy for the genus's tolerances. Depth in such small creeks and pools is shallow — on the order of a metre or less in the type habitat — though the species ranges through larger river channels as well; the IUCN assessment leaves formal depth limits blank, consistent with a shallow benthopelagic stream fish.
Feeding
No dedicated gut-content study of Tahuantinsuyoa chipi has been published, so its diet is inferred from its body plan, its trophic position and the habits of its relatives. FishBase places the species at a trophic level of about 3.2, the value typical of a small omnivore-to-invertivore rather than a dedicated predator or a herbivore. It is described as a benthopelagic fish — one that feeds near the bottom but also takes food in midwater — which fits a generalist forager working the substrate, leaf litter and lower water column of clear foothill streams.
In practice a fish of this size and guild in Amazonian piedmont creeks subsists on small benthic invertebrates (aquatic insect larvae such as chironomids and mayflies, micro-crustaceans and other meiofauna), supplemented by organic detritus, drifting items and incidental plant and algal material gleaned while foraging. Like most small cichlasomatines it almost certainly picks and sifts at the substrate rather than sieving sand wholesale in the manner of true eartheaters. In the community it functions as a mid-level consumer linking the stream's invertebrate production to larger fish predators.
Mating
The reproductive behaviour of Tahuantinsuyoa chipi has not been documented in detail in the wild, and the species is so rarely kept that few first-hand spawning accounts exist for chipi specifically. What is known of the genus comes overwhelmingly from its better-studied sister, Tahuantinsuyoa macantzatza, the 'Inca stone cichlid,' which is established in the hobby and whose behaviour is a reasonable guide to chipi's.
In that congener, and in cichlasomatine cichlids generally, the species forms monogamous pairs that establish and jointly defend a spawning territory. Pair formation runs through the usual cichlid sequence of lateral displays, jaw-locking and substrate cleaning, after which both partners share parental duties. Outside of breeding the fish are reported as relatively peaceful and even somewhat shy, but a bonded pair becomes territorial around the chosen spawning site and will drive off intruders. As with most small substrate-spawning cichlids, the principal social tension in a group setting is between rival pairs competing for the limited good spawning real estate rather than indiscriminate aggression toward unrelated tankmates.
Breeding
Tahuantinsuyoa chipi is a biparental substrate spawner, as documented for the genus through its sister species. In Tahuantinsuyoa macantzatza, eggs are laid on fallen leaves or pieces of submerged wood — surfaces the pair will relocate the brood among if disturbed — and both parents guard the clutch, with the adults taking the free-swimming larvae into the mouth to shelter and move them. This larvophilic mouth-sheltering on top of an open substrate spawn is a striking, somewhat intermediate strategy that has drawn attention to the genus among hobbyists. Specific clutch counts for chipi have not been published; small cichlasomatines of this size typically lay clutches on the order of one to a few hundred eggs, and the genus-typical figure should be read in that light rather than as a measured value for chipi.
After hatching, the pair continues to guard and herd the fry, which are moved between cleaned sites and defended until they are foraging independently. Reported triggers for spawning in the captive congener — and the most likely cues for chipi — are warm, soft, clean water, a conditioning diet of live foods such as whiteworms, and a slackening of large water changes to simulate the stable conditions of a settled stream pool. Because chipi itself has essentially not been bred in aquaria on any documented scale, these details are extrapolated honestly from Tahuantinsuyoa macantzatza and from the wider behaviour of the tribe, not recorded directly for the species.
In the aquarium
Tahuantinsuyoa chipi is, for practical purposes, not an aquarium fish: it is a Vulnerable, narrow-range Peruvian endemic that has barely entered the trade, and almost everything written about keeping 'Tahuantinsuyoa' in the hobby refers to its sister species, the Inca stone cichlid Tahuantinsuyoa macantzatza. The notes here are therefore offered as a careful extrapolation from that congener and from the requirements of comparable small cichlasomatines, with the explicit caveat that chipi itself is rarely if ever available and has no established husbandry track record.
On the genus's needs, a single pair of an 8-cm fish is comfortably housed in a tank of about 25–30 US gal or larger, longer and lower rather than tall, furnished to mimic a clear foothill stream. That means a sand or fine-gravel bottom, plenty of cover in the form of driftwood, leaf litter and rockwork, and flat stones, broad leaves or pieces of wood that can serve as spawning surfaces. Gentle to moderate, well-oxygenated flow suits a running-water fish; an external filter or a well-mature sponge filter and routine partial water changes keep the soft, clean conditions these clearwater cichlids prefer.
Water parameters drawn from the sister species point to soft, slightly acidic to neutral water — pH roughly 6.3–7.7, very low hardness (around 2–3 °dH), and a warm 77–82 °F. The fish accepts standard prepared foods but colours up and conditions best on a varied diet of live and frozen invertebrates — bloodworm, whiteworm, daphnia, brine shrimp — alongside a quality sinking pellet or flake.
Temperament, again by analogy with Tahuantinsuyoa macantzatza, is comparatively peaceful and even retiring for a cichlid: these are not boisterous fish, and they can be intimidated by fast, aggressive or much larger tankmates. Suitable companions in the genus's case are calm, medium-sized characins and other peaceful upper-Amazon community fish, avoiding tiny tetras and shrimp that may be eaten and avoiding robust cichlids that will dominate the tank. The chief friction comes when keeping multiple pairs in too small a space, where territorial disputes over spawning sites arise. None of this should be read as encouragement to seek chipi out — its conservation status and rarity make it a fish to admire in the wild and in the literature rather than to target for the tank.
Conservation
The IUCN Red List assesses Tahuantinsuyoa chipi as Vulnerable under criterion B1ab(iii) (assessed 22 April 2014 by L. Chocano and M. Hidalgo del Aguila; published 2016; assessment e.T49830312A53818163). The listing rests on a small extent of occurrence — about 6,500 square kilometres — restricted to the tributaries of the Pachitea and split across only four known locations, combined with a documented, continuing decline in habitat quality. The species is not known to occur within any protected area. Its population is presumed stable but is described as not abundant, and the assessment is flagged as needing updating.
The threats are specific and modern. The assessors single out water pollution from illegal gold mining — and the mercury contamination that accompanies it — together with pollution linked to illegal drug production, and increased nutrient loading, erosion and sedimentation from cattle ranching, all of which degrade the clear foothill streams the fish depends on. The species enters international ornamental trade, but at present that is not identified as a population-level pressure relative to habitat degradation. The assessment calls for further study of the species' distribution, abundance, breeding biology and threats, and for its inclusion in conservation planning for the Pachitea drainage. As a small endemic of a narrow Andean-piedmont range, Tahuantinsuyoa chipi is exactly the kind of fish whose fate is tied to the water quality of a handful of streams, and its Vulnerable status reflects how quickly that quality is being eroded.