Taxonomy & naming
Peckoltia wernekei was formally described by Jonathan Armbruster and Nathan Lujan in 2016 in ZooKeys (volume 569, pages 105–121), under the title 'A new species of Peckoltia from the upper Orinoco (Siluriformes, Loricariidae)'. The holotype (AUM 54314) was collected from Marujeta Creek, 99 mi east of San Fernando de Atabapo, in the Ventuari River drainage of Amazonas State, Venezuela (4°17'41.3"N, 66°17'20.0"W). The Catalog of Fishes (Eschmeyer, CAS) lists the current valid combination as Peckoltia wernekei Armbruster & Lujan 2016, with no synonyms.
The species epithet honours David C. Werneke, Fish Collections Manager at the Auburn University Museum and a close colleague of the first author — a patronym rather than a descriptive name. The genus Peckoltia was erected in recognition of Gustavo Peckolt, a nineteenth-century Brazilian botanist who participated in the Natural History Commission of Rondon.
Within the subfamily Hypostominae (tribe Ancistrini; Armbruster 2004), Peckoltia is a well-defined clade of medium-sized, pattern-bearing plecos characterised by a medially divided or partially reduced adipose fin, tricuspid teeth, and strong interopercular odontodes in males. P. wernekei is one of the smaller members of the genus, reaching only ~4 in SL according to FishBase, and sits within a species group characterised by vivid orange-yellow reticulate patterning. In the aquarium hobby it was in circulation as LDA086 and L243 before its formal description, reflecting two independent DATZ coding events for the same animal.
Morphology
Adults reach approximately 4 in standard length (SL), making P. wernekei a mid-sized member of its genus — large enough to hold its own in a community aquarium but far more compact than the largest Hypostomus or Pterygoplichthys. The body plan follows the typical Peckoltia template: dorsoventrally somewhat compressed, with a broad, flat ventral surface and a humped dorsal profile behind the nuchal plate. The body and fins are armoured by overlapping bony scutes.
The coloration is the species' most recognisable feature: a rich dark brown to blackish ground colour blanketed with irregular, rounded blotches of orange to orange-yellow. In aquarium specimens these blotches may appear more intensely orange under warm white lighting. The pattern extends onto all fins. Juveniles are similarly patterned.
Sexual dimorphism follows the Peckoltia norm. Males develop short odontodes on the leading edge of the pectoral-fin spine and on the posterior half of the body; in breeding condition the interopercular odontodes (cheek bristles) become more pronounced. Females show no such odontodes but develop a noticeably broader body profile, particularly in the region immediately posterior to the pectoral fins, which is the most reliable sexing character when the fish is viewed from above. Ripe females also develop a distinctly convex belly profile.
Habitat
The known range of P. wernekei is restricted to the Ventuari River drainage within Amazonas State, Venezuela — a blackwater tributary of the upper Orinoco rising on the Guiana Shield. The Ventuari is an igapo-influenced river with naturally acidic, softwater conditions: pH values below 6.0 and very low conductivity are characteristic. The type locality, Marujeta Creek (ca. 4°17'N, 66°17'W), is a small blackwater stream some 99 mi east of San Fernando de Atabapo.
Field data from IUCN assessors and from the original description indicate rocky substrates within swift to moderate current, with submersed rock surfaces and root tangles providing shelter. This Guiana Shield habitat is structurally different from the whitewater, Andean-influenced rivers associated with many hobbyist plecos — the water is clear, dark-tinted by tannins, soft, and relatively cool by Amazonian standards (approximately 75–79 °F). The restricted range (a single river drainage) underlies the Near Threatened IUCN assessment from 2019.
P. wernekei has not been recorded outside the Ventuari system, and there is no evidence of introduced populations elsewhere.
Feeding
In common with other Peckoltia species, P. wernekei is primarily an algae grazer and biofilm scraper in the wild. The ventrally positioned mouth, equipped with rows of fine, tricuspid teeth, is well adapted to rasping epilithic algae and associated periphyton from rock surfaces in moderate current. Organic detritus, fine particulate matter, and benthic invertebrates likely supplement the diet opportunistically.
In captivity, a plant-based diet is appropriate: algae wafers and spirulina-based sinking pellets should form the dietary staple. Blanched vegetables — courgette (zucchini), cucumber, sweet potato, and green beans — are accepted and provide dietary diversity. A small proportion of protein-rich food (bloodworm, shrimp, or catfish pellets with a higher protein content) can be offered occasionally; this is particularly useful when conditioning fish for breeding. Driftwood should be present in the aquarium so the fish can rasp its surface for biofilm, even though P. wernekei is not a wood-eater in the manner of Panaqolus or Panaque. Rock surfaces colonised by microalgae in a well-lit aquarium will also be utilised.
Mating
No wild breeding observations have been published for P. wernekei specifically. Courtship behaviour can be inferred from the genus-level pattern established for other Peckoltia species, and from the dimorphism data provided by Armbruster & Lujan (2016). Males are territorial around potential spawning sites — a cave, tight crevice, or hollow piece of driftwood — and display actively, extending and fanning the caudal fin and extending interopercular odontodes laterally. Rival males may engage in mouth-lock skirmishes.
Females in breeding condition show a distinctly broader body profile, particularly posterior to the pectoral fins — a feature specifically noted for this species in the original description and on PlanetCatfish. A receptive female will be shepherded into the male's chosen cavity, where spawning occurs. Unlike the large wood-gouging Panaque, Peckoltia does not excavate its own hollow; it relies on pre-existing cavities.
In the aquarium, the provision of ceramic breeding tubes, coconut-shell caves, or tight sections of hollow driftwood replicates the natural spawning habitat. Conditioning pairs with varied, high-quality food and performing regular water changes with slightly cooler replacement water can help trigger spawning behaviour.
Breeding
Peckoltia wernekei has not been reported as successfully bred in captivity as of the PlanetCatfish breeding-report register (no reports logged). Given its close affinity to other Peckoltia species (such as P. compta, P. vittata, and P. sabaji) that have been bred in aquaria, a similar cave-spawning protocol is expected to apply.
General Peckoltia breeding follows the standard loricariid pattern: the male selects and defends a narrow cave or tube, and after spawning he fans the eggs with his pectoral fins to maintain oxygenation and removes any that fungus. Egg clutches in related species typically number several dozen adhesive eggs. Incubation at approximately 77 °F takes around 4–6 days; fry absorb the yolk sac over the following week and begin active feeding on algae and soft foods. Paternal guarding continues until fry disperse.
The blackwater origin of P. wernekei suggests that soft, acidic water conditions may improve breeding success compared with harder, more neutral parameters. Maintaining pH in the 5.8–6.8 range and keeping conductivity low (below 150 µS/cm) is advisable when attempting to condition this species for reproduction. Regular partial water changes with reverse-osmosis or rainwater are helpful in achieving these parameters in tap-water-based systems.
In the aquarium
Peckoltia wernekei is an attractive, moderately active, and generally peaceful pleco suitable for a wide range of community set-ups. Its modest adult size — under 4.5 in SL — means a single specimen can be accommodated in a 100-litre aquarium, though 40–55 US gal affords more natural foraging space and greater compatibility with territorial tankmates. A pair or trio requires correspondingly more space and multiple caves to reduce male competition.
Water chemistry should reflect the blackwater upper-Orinoco origin: temperature 75–81 °F, pH 5.8–7.0, very soft to moderately soft water (up to ~100 µS/cm conductivity or approximately 4–6 °dH is ideal; the species can tolerate harder water but breeding is unlikely). Strong filtration with good oxygenation is important; the Ventuari is a fast-flowing clear-water system and P. wernekei will not thrive in stagnant, poorly oxygenated conditions.
Rock caves and tight crevices are essential furnishings — this fish spends most of the day sheltering and becomes active at dusk. Pieces of smooth water-worn rock or slate arranged to create narrow tunnels closely mimic natural habitat. Driftwood is a welcome addition for perching and biofilm feeding. Plants are generally safe.
Compatibility: peaceful toward other species and generally ignores fish too large to compete for caves. Males of the same species (or similarly sized plecos) may skirmish, so provide ample cave sites if keeping multiple individuals. Safe with small tetras, dwarf cichlids, apistogrammas, and other species adapted to soft, acidic conditions. Not suitable for large cichlid set-ups where it could be bullied or damaged.
Conservation
The IUCN Red List assessed Peckoltia wernekei as Near Threatened (NT) in 2019, under criterion B1b(iii)+2b(iii). This assessment reflects the species' highly restricted distribution — confirmed only from the Ventuari River drainage — combined with documented decline in habitat quality due to artisanal gold mining (garimpo) in the region, which degrades water clarity, increases sedimentation, and releases mercury into the watershed. The estimated extent of occurrence (EOO) is below the NT threshold.
Ornamental collection for the aquarium trade also applies pressure to local populations, although the scale of harvest relative to wild population size has not been formally quantified. The combination of small range, a single-river endemic status, and ongoing threats from mining places P. wernekei in a precarious position.
Aquarists who value this species have a role to play: captive propagation efforts and knowledge of the species' requirements would help establish a self-sustaining ex-situ population, reducing reliance on wild-caught imports. There are currently no captive breeding reports on record at PlanetCatfish. The collection and export of this species is governed by Venezuelan fisheries regulations, and responsible acquisition from reputable suppliers who can verify sustainable sourcing is encouraged.