Taxonomy & naming
Microglanis maculatus was described by Oswaldo Shibatta in 2014. It belongs to the family Pseudopimelodidae, the bumblebee and dwarf pimelodid catfishes, a group that was long lumped into or confused with Pimelodidae before being recognised as its own family. The genus Microglanis contains numerous small, superficially similar species across South America, several of them described only in the last few decades as researchers worked through cryptic diversity in Brazilian river basins.
The genus name Microglanis combines Greek mikros ("small") with glanis, an old name for a catfish, describing the genus's diminutive members. The species epithet maculatus is Latin for "spotted", referring to the rounded dark spots scattered over the body that distinguish this species from its congeners. As with many recently described Microglanis, older aquarium literature and trade labels may not distinguish it from similar-looking bumblebee catfish sold under the genus name alone; the Catalog of Fishes treats Microglanis maculatus as the current valid name.
Morphology
This is a genuinely small catfish: FishBase records a maximum size of only about 1.5 in standard length, among the smallest of the pseudopimelodids. The body carries the family's typical broad head and stout barbels, with a ground colour pale enough to set off a pattern of well-defined, rounded dark spots along the flanks — the feature the species is named for. The caudal fin is emarginate (shallowly notched rather than deeply forked or rounded).
Like other Microglanis and pseudopimelodids, the skin is scaleless (naked), a trait shared across most catfish groups and one that matters directly for medication dosing (see "In the aquarium"). Data on distinguishing males from females is sparse; no dimorphic colour or shape difference has been documented for this species.
Habitat
Microglanis maculatus is known from the Rio dos Patos basin and the upper rio Tocantins basin in Goiás State, Brazil, with its type locality in the ribeirão Pouso Alegre area. It is a freshwater, demersal (bottom-dwelling) species found around creek mouths with riparian vegetation overhanging the water, on rocky substrates mixed with sand, clay, submerged logs and branches — exactly the kind of structure-rich cover a small, secretive night forager needs.
The habitat is shallow: recorded depths at collection sites are only around 2.5 in. Recorded water conditions include a minimum temperature of 73 °F and a pH of 7.65 at the collection site, indicating a warm, close-to-neutral stream environment rather than the deeply acidic blackwater sometimes assumed for small South American catfish.
Feeding
Microglanis maculatus is a nocturnal, bottom-foraging omnivore/micro-predator, consistent with its genus and family. By day it stays hidden among rock, wood and leaf litter; after dark it moves over the substrate hunting small invertebrates and other prey, taking anything roughly up to about half its own body length. Aquarium reports describe it as an undemanding scavenger.
In the aquarium it accepts standard sinking foods, prepared pellets and frozen fare without difficulty. Because it is a night feeder, offering food after lights-out — or ensuring a sinking portion reaches the bottom once tankmates have settled — helps this small, retiring catfish get its share rather than being out-competed by more active daytime fish.
Mating
No description of courtship or spawning behaviour for Microglanis maculatus specifically was found in the cached sources. Aquarium notes for the species mention that softer, slightly acidic water is thought to favour breeding, which fits the generally warm, close-to-neutral stream habitat it is collected from, but the actual pairing or spawning sequence has not been documented in the material available here. Data sparse — no confirmed courtship account for this species.
Breeding
Breeding of Microglanis maculatus in the aquarium is not documented in the cached sources, and no confirmed spawning mode (egg-scattering, cave-spawning, or otherwise) has been recorded for this species specifically. Given its family, close relatives in Pseudopimelodidae and Microglanis are generally understood as egg-layers with little to no parental care, but this should not be treated as confirmed for M. maculatus without direct evidence. Prospective breeders should treat any attempt as experimental: provide the soft, slightly acidic, warm water suggested by aquarium sources, plenty of cover, and expect that a captive spawn — if it happens — is not a routine, well-documented event for this species.
In the aquarium
Microglanis maculatus stays genuinely tiny — about 1.5 in as an adult — so it is one of the rare catfish where the usual "size trap" runs the other way: this is a fish that will not outgrow a modest aquarium, but its small size does mean it can itself become prey to larger tankmates and needs correspondingly small, peaceful company. A well-planted or wood-and-rock aquascape with hiding places by day suits its nocturnal, secretive habits; expect to see it mostly after the lights go down.
As a scaleless catfish, it is medication-sensitive in the same way as loaches, puffers and eels — dose copper-based treatments and many standard medications conservatively, often at reduced strength. Handle it gently in a net or, better, scoop it in a container; while its spines are far less formidable than those of larger catfish, the same locking-spine caution that applies across Siluriformes is good practice. Water reports point to warm (73 °F or above), close-to-neutral to slightly acidic conditions rather than hard alkaline water — match the stream conditions noted in its native range rather than assuming deep blackwater softness.
Conservation
The IUCN Red List assesses Microglanis maculatus as Least Concern, an assessment made in 2018. It is known only from a limited area of Goiás State, Brazil — the Rio dos Patos basin and the upper rio Tocantins basin — so despite the LC status its range is narrow by comparison with widespread South American catfish, and its conservation outlook depends on the health of those specific headwater streams and their riparian vegetation rather than any broad, continent-wide safety margin.