Taxonomy & naming
Hypostomus kopeyaka was formally described by Carvalho, Lima, and Zawadzki in 2010 in Neotropical Ichthyology (volume 8, number 1), from holotype MZUSP 98764 — a 9 in SL individual collected from the rio Tiquié, a tributary of the rio Uaupés within the upper rio Negro drainage of Brazil. The Catalog of Fishes (Eschmeyer, CAS) recognises the valid combination Hypostomus kopeyaka.
The species was described alongside Hypostomus weberi, also from the upper rio Negro, in the same paper. Together they were assigned to the Hypostomus cochliodon group as defined by Armbruster (2003), a clade distinguished by a small number of spoon-shaped (cochleariform) teeth and a dentary angle averaging less than 80°. Among H. cochliodon group members, H. kopeyaka is diagnosed by a unique colour pattern of conspicuously horizontally elongated, closely-set black spots covering the head and entire dorsal and lateral body surfaces — a pattern unlike the large, rounded, widely-spaced black spots of its paper-mate H. weberi.
The distribution may extend westward into Departamento Vaupés, Colombia, given the transboundary character of the rio Tiquié watershed, but FishBase records the confirmed type locality in Brazil. The species epithet is drawn directly from the indigenous name given to this fish by the Tukano and Tuyuka people of the upper Negro.
Morphology
The holotype measured 9 in SL (roughly 9 in), representing the known maximum size from the original description. The body plan follows the Hypostomus ground pattern: the fish is encased in rows of overlapping keeled bony scutes along the flanks, the underside is unplated and pale, and the head is broad and flattened with large eyes positioned laterally.
The most diagnostic morphological features place H. kopeyaka firmly in the H. cochliodon group: the teeth are bicuspid, numbering 10–13 in observed specimens, with distinctly rounded mesial cusps rather than the sharper, more numerous cusps found in most other Hypostomus. The dentary angle averages less than 80°, a geometric trait measured in the original description as a key clade character. These spoon-shaped teeth are better suited to biting into soft or decayed submerged wood than to scraping hard rock surfaces.
The colour pattern is the most immediately striking feature: horizontally elongated black spots, set closely together, tile the head and all dorsal and lateral surfaces. This gives the fish a streaked or smudged appearance that differs markedly from the spotted patterns of most Hypostomus. No detailed data on sexual dimorphism are available from the original description; the species likely follows the general Hypostomus pattern in which odontodes on the pectoral spine and body are more developed in males.
Habitat
Hypostomus kopeyaka is known from the rio Tiquié, a blackwater tributary of the rio Uaupés that feeds the upper rio Negro system of the Amazon basin. The upper rio Negro is one of the most chemically distinctive river systems in the world: the water is heavily stained with dissolved humic and fulvic acids, yielding a deep tea-brown colour, extremely low conductivity (often below 10 µS/cm), and a pH typically in the range of approximately 4.0–5.5. Dissolved oxygen is adequate at the surface and in moving stretches but can be low in slow or stagnant sections — a selective pressure for the facultative air-breathing capacity documented in Hypostomus.
Water temperatures in the upper Negro system typically range from approximately 79–86 °F through most of the year, with modest seasonal variation. The substrate of rio Tiquié is characteristic of blackwater Amazonian drainages: granite and sandstone bedrock in the upper reaches, with abundant submerged wood, leaf litter, and flooded forest margins during high water. The name 'kope yaka' — pleco from the holes — is consistent with a microhabitat preference for rock crevices, sunken logs, and flooded bank cavities where the fish wedge themselves to feed and shelter.
Feeding
The cochleariform (spoon-shaped) teeth of the H. cochliodon group are widely interpreted as an adaptation for extracting material from soft or partially decayed wood. Unlike the fine-toothed scraping apparatus of algae-specialist loricariids, the rounded cusps of H. kopeyaka and its relatives are suited to biting off fragments of waterlogged timber and engulfing the associated microbial biofilm, fungi, and fine organic debris that colonise submerged wood in blackwater rivers.
Direct feeding observations in the wild are absent from the literature for this species. By comparison with other well-studied H. cochliodon group members, the diet is expected to centre on wood and associated organic matter, supplemented opportunistically by algae, detritus, and microinvertebrates where available. In the acid-blackwater environment of the upper Negro, primary productivity is low and biofilm communities on submerged surfaces provide an important resource for bottom-feeding loricariids.
Mating
No specific observations of mating behaviour in Hypostomus kopeyaka have been published. Within the genus Hypostomus, mating is typically associated with cave or crevice sites where the male takes a territorial position. Males of most Hypostomus develop more pronounced odontodes on the pectoral spines and interopercular plates during reproductive condition, and agonistic interactions between males around prime nesting sites are characteristic.
Given the fish's indigenous name — 'pleco from the holes' — and its association with rocky, crevice-rich microhabitats, it is plausible that H. kopeyaka uses deep rock fissures or hollow logs as breeding sites, consistent with the general pattern in rock-dwelling Hypostomus. Confirmation awaits field study or captive observations.
Breeding
No breeding data for Hypostomus kopeyaka have been published in the scientific literature or, as of the time of writing, documented in the aquarium hobby. The species has not entered the ornamental trade in meaningful numbers, and its remote origin in the upper rio Negro makes collection logistically demanding.
By analogy with the broader Hypostomus breeding template — paternal cave guarding of adhesive egg clutches, with the male fanning and defending eggs through an incubation of several days — similar behaviour is anticipated but remains unconfirmed for this species. Any hobbyist fortunate enough to obtain verified specimens would be in a position to contribute substantially to knowledge of this taxon.
In the aquarium
Hypostomus kopeyaka has not established itself in the ornamental trade and is essentially unknown in hobbyist circles as of 2026. The few individuals that have reached aquarists outside Brazil are unlikely to be widely available, and verified captive specimens have not been recorded in major hobby databases.
For any keeper who does obtain this fish, the blackwater origin dictates the husbandry framework. Soft, acidic water is not merely preferable but is the native condition: pH in the range of approximately 4.5–6.0, very low conductivity, and good oxygenation would most closely replicate the rio Tiquié environment. Temperatures around 79–86 °F are appropriate. Filtration should be efficient but flow moderate; the upper Negro is not a whitewater torrent, and very high current is not required.
Hiding spaces — crevice-forming rockwork, hollow driftwood sections — are important given the species' apparent preference for hole-dwelling. A diet centred on submerged driftwood, supplemented with algae wafers and vegetable matter, aligns with the cochleariform-toothed wood-eating biology of the H. cochliodon group. The elongated-spot colour pattern is striking and distinctive, making this a visually rewarding specimen for the specialist blackwater aquarist prepared to meet its needs.
Conservation
The IUCN Red List assessed Hypostomus kopeyaka as Least Concern in November 2018. The assessment reflects the remoteness of the species' known habitat — the upper rio Negro and rio Tiquié system sits within or adjacent to protected Amazonian indigenous territories, and direct anthropogenic pressure on the type locality is limited relative to more accessible regions.
The species' distribution appears genuinely narrow, known with certainty only from the rio Tiquié basin, though a westward extension into Colombian Vaupés is possible. Blackwater Amazonian systems face diffuse long-term risks from deforestation, atmospheric nitrogen deposition, and climate-driven hydrological change, though these operate slowly over large areas. The IUCN LC assessment is not a guarantee against local threats; the restricted range means any significant alteration of upper rio Tiquié hydrology could affect this species without triggering reassessment for years. Ongoing monitoring of endemic blackwater loricariids in the upper Negro would be scientifically valuable.