Taxonomy & naming
Microglanis pleriqueater was described in 2013 by Mattos, Ottoni & Barbosa in Ichthyological Exploration of Freshwaters (volume 24: 147–154), from the São João river basin in Rio de Janeiro state, southeastern Brazil. It sits in the genus Microglanis, part of the family Pseudopimelodidae — the bumblebee catfishes and their relatives, a group of small, heavy-headed, scaleless catfishes that was carved out of the older, broader Pimelodidae as the family was reorganised on molecular and morphological grounds. Older literature and museum labels for this genus may still turn up under a plain "Pimelodidae" heading; the Catalog of Fishes treats Pseudopimelodidae, and the combination Microglanis pleriqueater, as current.
The genus name Microglanis is Greek, from mikros ("small") and glanis (an old name for a catfish), a straightforward reference to the diminutive size typical of the genus. The species epithet pleriqueater is a Latin coinage from plerique ("most, the majority") and ater ("black"), alluding to the dark brown to black ground colour that dominates most of the body. The describers noted the new species as morphologically close to Microglanis nigripinnis and M. ater, distinguishing it on details of pigmentation banding and fin-ray counts, including 15–16 principal caudal-fin rays.
Morphology
Microglanis pleriqueater is a tiny catfish even by the standards of its small-bodied genus: the type series was based on specimens around 1.5 in SL, and the species does not appear to grow much beyond that. It has the typical pseudopimelodid build — a broad, somewhat flattened head, a stout body tapering to the tail, and three pairs of barbels used to feel out food and surroundings in the dark. The body is naked, without scales, which is standard for the family but matters directly for aquarium medication.
Colouration is dark brown to black over most of the body, broken by three whitish-brown bands crossing the flank — the banding pattern is one of the main features separating it from its close relatives M. nigripinnis and M. ater. As in other Microglanis and pseudopimelodids, the dorsal and pectoral fins carry stiff spines that can be locked erect; while this genus is small and its spines are correspondingly modest, the same handling caution that applies to bigger spined catfish is worth keeping in mind.
Habitat
The species is known only from short coastal river drainages of Rio de Janeiro state in southeastern Brazil: the São João river basin, its type locality (recorded near Conceição), and a confirmed range extension into the neighbouring Macabu river basin to the east. Both are Atlantic-slope systems draining directly to the sea rather than part of the Amazon or Paraná basins, and coastal drainages of this kind are often home to small, narrowly distributed endemics that go undetected for a long time.
The cache does not give a documented temperature or pH profile from the original description or the range-extension paper. As a small, benthic, cover-seeking Microglanis from a warm lowland Brazilian coastal stream, moderate tropical temperatures and soft-to-neutral water are a reasonable working assumption for the genus, but hobbyists should treat exact figures as unconfirmed for this specific species and mirror the general Microglanis guidance rather than treat it as verified for M. pleriqueater.
Feeding
Microglanis species are nocturnal benthic micro-predators, foraging over the stream bottom after dark for aquatic invertebrates. Diet notes for the genus point specifically to insect larvae — chironomid (non-biting midge) and mayfly larvae feature heavily in natural diets — alongside other small invertebrates picked up along the substrate.
In the aquarium, Microglanis species accept frozen and live foods readily: bloodworm, brine shrimp, mosquito larvae and small worms are all reported to be taken, and sinking pellets round out a captive diet. Because they are night foragers, feeding after the lights go out gives them a fair chance against faster, more visible tankmates that would otherwise clean up the food first.
Mating
No courtship or spawning behaviour has been documented for Microglanis pleriqueater specifically; the original description and the follow-up range-extension record are both taxonomic/distributional papers, not breeding accounts. General Microglanis literature notes a preference for soft, slightly acidic water as a spawning trigger, consistent with many small tropical benthic catfish that key breeding activity to seasonal rain and softening water, but no pairing or courtship detail is available for this species.
Breeding
There is no confirmed aquarium or field breeding account for Microglanis pleriqueater in the available sources. As with many small, recently described, narrow-range catfish, it should be treated as essentially unbred in the hobby and largely unstudied in the wild for reproductive biology. Prospective keepers should not assume any particular spawning mode (egg-scattering, cave-spawning or otherwise) for this species specifically — the data are simply not there yet, and any wild-collected or occasionally traded specimens should be assumed to be exactly that: wild-collected, not captive-bred.
In the aquarium
Microglanis pleriqueater stays genuinely small — the type specimens measured around 1.5 in SL — so it is one of the rare catfish that does not spring the usual size trap; a modest, well-furnished tank suits it for life. That said, it is a scaleless catfish, so it carries the same medication sensitivity as loaches, puffers and eels: dose copper-based treatments and many general medications conservatively, often at half strength, and watch the fish's response closely.
Provide caves, driftwood, leaf litter or dense cover, since like other Microglanis it is a nocturnal, hide-dependent fish that will be rarely seen by day and much more active after lights-out. Handle it gently and avoid tangling it in a net; even at this small size the dorsal and pectoral spines can lock and snag mesh. Given the total absence of confirmed water-chemistry data for this specific species, keepers are best served by erring toward the moderate, soft-to-neutral tropical conditions reported for the genus generally, rather than assuming any extreme. This is a species for the specialist small-catfish keeper rather than a routine community tankmate, given how little is documented about its needs.
Conservation
Microglanis pleriqueater has not been evaluated by the IUCN Red List (Not Evaluated). It is known from only two neighbouring coastal river basins in Rio de Janeiro state — the São João and Macabu basins — a genuinely narrow range for a described species. Coastal Atlantic Forest drainages in this part of Brazil face heavy pressure from urbanisation, agriculture and historic deforestation, so a species with this restricted a distribution likely warrants conservation attention even though no formal assessment yet exists.
Because the species is so poorly known — a single description and one range-extension note make up essentially the whole published record — its population trend, abundance and any threats specific to it are simply undocumented. Any specimens reaching the aquarium trade should be assumed wild-collected from a narrow-range endemic, which is itself a reason for caution rather than casual acquisition.