Taxonomy & naming
Ancistrus clementinae was described by Hialmar Rendahl in 1937 in Arkiv för Zoologi (volume 29, part 3A, article 11, p. 4, fig. 2), from specimens collected in the Río Clementina system northwest of Babahoyo, Ecuador. FishBase assigns it the identifier 50247 and cites Sonia Fisch-Muller's 2003 Checklist of the Freshwater Fishes of South and Central America (Reis, Kullander & Ferraris, eds.) as the primary modern reference. The Catalog of Fishes (Eschmeyer, CAS) recognises Ancistrus clementinae Rendahl, 1937 as the valid name.
The genus Ancistrus is one of the largest within Loricariidae and belongs to the tribe Ancistrini, subfamily Hypostominae. The name Ancistrus derives from Greek agkistron (hook), a reference to the curved, hook-like interopercular odontodes (cheek spines) found in both sexes — particularly prominent in males. These interopercular odontodes are a synapomorphy of Ancistrus and help distinguish the genus from the superficially similar Chaetostoma and Hypostomus.
The species epithet clementinae is a toponym, honoring the type-locality river system — the Río Clementina — rather than a person. The Río Clementina drains into the Guayas system, Ecuador's largest Pacific-slope watershed.
Ancistrus clementinae belongs to a clade of Pacific-slope Ecuadorian bristlenoses that also occurs in the Santa Rosa, Catamayo, and Canayacu river drainages (Aguirre et al. 2014; Jiménez-Prado et al. 2015; Provenzano and Barriga-Salazar 2018), suggesting the species is more widely distributed on the Ecuadorian Pacific slope than the type locality alone implies.
Morphology
Ancistrus clementinae reaches a maximum recorded size of 4 in standard length (SL) — a typical Ancistrus size, placing it firmly in the 'dwarf to medium bristlenose' category. The body is covered in overlapping bony scutes and has the gently depressed, broad-headed profile characteristic of the genus.
The most distinctive feature of mature males is the presence of branched, fleshy tentacles erupting from the snout and around the rostral margin. These soft, multi-branched appendages — sometimes called 'bristles' or 'whiskers' in the hobby — are the defining visual character of the genus Ancistrus. In females, tentacles may be present along the snout margins but are far less developed: shorter, fewer, and less elaborately branched than in males. In juveniles of both sexes the tentacles are absent or rudimentary and develop as the fish matures.
The interopercular region bears stiff, elongate odontodes (the 'hooks' implicit in the genus name) that are more numerous and longer in males. Coloration is not well documented for this species specifically; Ancistrus in general display browns, greys, and olive hues, often with small pale spots or mottling.
PlanetCatfish photographs (by W. Aguirre) show lateral, dorsal, and ventral views, providing the best visual reference currently available for the species.
Habitat
Ancistrus clementinae inhabits the Pacific-slope river drainages of western Ecuador. The type locality is the Río Clementina system northwest of Babahoyo, in the Guayas drainage — Ecuador's principal Pacific-slope river basin. Subsequent ichthyological surveys have recorded the species in the Santa Rosa, Catamayo, Canayacu, Siete, Caluma, and Bucay rivers (Aguirre et al. 2014; Jiménez-Prado et al. 2015; Provenzano and Barriga-Salazar 2018), indicating it is distributed across a substantial portion of the Ecuadorian Pacific coast, with an estimated extent of occurrence of 15,493–32,131 mi² (IUCN 2021).
The IUCN assessment classifies the habitat as inland wetlands. The rivers of the Ecuadorian Pacific slope descend from the western Andes through tropical and subtropical forest, delivering warm, turbid water during the wet season and clearer, lower flows in the dry season. FishBase characterises the species as demersal freshwater and notes facultative or obligate air-breathing capability — a trait shared by some Ancistrus and consistent with periodic low-oxygen conditions in warm lowland rivers.
Specific water chemistry data (temperature, pH, hardness) from the species' range are not available in the cached sources.
Feeding
Ancistrus clementinae feeds in the manner of the genus: primarily as an algae scraper and biofilm grazer, using its ventrally placed, toothed sucker-mouth to rasp attached algae, diatoms, and organic material from hard surfaces including submerged rocks, wood, and roots. Ancistrus are less committed wood-eaters than Panaqolus or Panaque, though they will rasp softer, degraded wood surfaces and benefit from having driftwood present.
PlanetCatfish recommends a vegetarian diet in the aquarium: algae wafers, spirulina-based foods, courgette (zucchini), cucumber, and small amounts of meaty food. This reflects the typical Ancistrus dietary profile — predominantly plant and algae based, with protein as a minor supplement rather than a staple. In the wild, biofilm communities on submerged substrates are likely the primary food source.
Mating
Ancistrus as a genus are well-studied cave-spawners in the aquarium hobby, and A. clementinae likely follows the same reproductive pattern, though no breeding reports for this species specifically are on record at PlanetCatfish. Mature males become territorial around caves and crevices, particularly hollow pieces of driftwood, ceramic tubes, or rock caves, which serve as spawning sites. Males display their branched rostral tentacles — more elaborate in older, dominant males — and may engage in pushing contests with rival males.
Male Ancistrus can be aggressive toward conspecific males in enclosed spaces, and keeping more than one male in a tank smaller than 40 US gal risks chronic stress and injury. A single male with multiple females is the standard management approach. Females approach the male's territory to inspect the cave before spawning.
Breeding
Ancistrus clementinae is a cave-spawning loricariid with paternal brood care — the reproductive strategy shared by the entire genus and the source of Ancistrus's popularity as a reliably bred aquarium fish. Although no aquarium breeding reports specific to A. clementinae are documented, the species' care and reproduction are expected to follow the well-established Ancistrus template.
The male prepares and defends a cave (hollow driftwood, ceramic tube, or rock cavity). After courtship, the female deposits her adhesive eggs on the cave walls or roof. The male then assumes exclusive brood care: he remains in the cave, fanning the eggs with his pectoral and pelvic fins to maintain oxygenation, and periodically cleaning them. Incubation typically takes five to seven days at tropical temperatures; fry emerge looking like miniature adults and begin grazing almost immediately.
Conditioning adults with a varied vegetarian diet, regular substantial water changes, and a slight temperature drop can trigger spawning. Providing multiple caves allows the male to select his preferred site and gives females refuge from persistent males.
In the aquarium
Ancistrus clementinae is a seldom-imported Ecuadorian bristlenose that is expected to be kept very much like other small Ancistrus — one of the most beginner-friendly pleco groups in the hobby. Its modest adult size (around 4 in SL) makes it manageable in tanks of 20 US gal or more, and it is peaceful toward other species.
The essential setup requirements are a piece of driftwood (for grazing and shelter), at least one cave or hollow log for male territory and potential spawning, and clean, well-filtered water with regular partial water changes. Strong current is not required; standard aquarium filtration providing moderate flow is adequate. Temperature should reflect the tropical lowland environment: approximately 72–79 °F.
PlanetCatfish notes that males may be territorial with conspecifics, so multiple males should only be kept together if the aquarium is spacious and well-furnished with hiding places. The species is compatible with peaceful community fish — small tetras, rasboras, Corydoras, and livebearers are suitable tankmates.
Although no breeding records for this species are on file, hobbyists experienced with other Ancistrus are well-placed to attempt its reproduction, as the conditions required (cave, good water quality, plant-based diet) are identical to those proven for close relatives.
Conservation
Ancistrus clementinae was assessed by the IUCN Red List as Least Concern in 2021, based on an assessment carried out on 24 September 2020 (Lyons 2021: e.T176675557A176675563). The justification cites a broad distribution across multiple Pacific-slope drainages of Ecuador — Guayas, Santa Rosa, and Catamayo river systems among others — with an estimated extent of occurrence of 15,493–32,131 mi². No range-wide population decline sufficient to trigger a threatened category was identified, and the species is well-represented in ichthyological collections.
The assessment nonetheless identifies ongoing threats: deforestation, agricultural production, pollution, and artisanal mining on the Ecuadorian Pacific slope are causing continuing habitat quality decline. Population trend is listed as Unknown, reflecting limited monitoring data. The species is native only to Ecuador (mainland).
The Ecuadorian Pacific slope is one of the world's most biodiverse and threatened regions — part of the Tumbes-Chocó-Magdalena biodiversity hotspot — and freshwater biodiversity here is under sustained pressure from land-use change. While A. clementinae currently appears to be resilient enough to carry a Least Concern rating, sustained degradation of river catchments could alter that status in future assessments.