Taxonomy & naming
Microglanis cibelae was described by Luiz Roberto Malabarba and Cristina L. Mahler in 1998. It belongs to the family Pseudopimelodidae, the bumblebee and dwarf pimelodid catfishes, a group that was long lumped into Pimelodidae before being split out as its own family. The genus Microglanis contains a few dozen small South American species, several of which share the boldly blotched "bumblebee catfish" pattern sold in the aquarium trade.
A later molecular and morphological reappraisal of the genus (cited in the scientific literature) has suggested that M. cibelae may be a junior synonym of the earlier-described Microglanis cottoides, which would make cottoides the senior valid name for this lineage. That question has not been fully resolved in the aquarium hobby's usage, so this profile continues to treat cibelae as Malabarba & Mahler described it, keeping the genus Microglanis as given.
Morphology
Microglanis cibelae is a small catfish, reaching only about 3 in standard length even as an adult — a genuinely dwarf species rather than one that merely looks small when young. Like other pseudopimelodids it has a broad, flattened head, a stout body tapering toward the tail, and three pairs of barbels used to feel out food on the bottom.
The skin is naked — Microglanis, like most catfishes, has no scales — which makes it noticeably more sensitive to copper-based and some other medications than a scaled fish; treatments should be dosed conservatively. As in other pimelodid-type catfishes it carries stiff, serrated spines at the leading edge of the dorsal and pectoral fins that can lock erect and snag in a net, so it is best scooped and moved in a container rather than chased with a net.
Habitat
The species is endemic to a cluster of short, independent coastal river drainages in northern Rio Grande do Sul and southern Santa Catarina states, in the Atlantic Forest region of southern Brazil — a much more restricted range than the wide Amazonian and Orinoco basins occupied by many South American catfishes.
Detailed water-chemistry data for the type localities is sparse, but the genus as a whole is described as tolerant of a range of conditions in captivity, while breeding condition is best approximated with softer, slightly acidic water, in keeping with the coastal, forest-influenced streams it comes from.
Feeding
Microglanis cibelae is a nocturnal benthic omnivore, foraging along the substrate after dark for small invertebrates, detritus and other opportunistic food items — the typical diet of small pseudopimelodid catfishes.
In the aquarium it is undemanding and will take standard sinking pellets, frozen foods and other prepared foods readily. Because it feeds mainly at night, offering food after the lights go out helps ensure it gets a fair share in a community tank rather than being out-competed by more visible daytime feeders.
Mating
Specific courtship behaviour for Microglanis cibelae has not been documented in the available sources. The wider genus is reported to spawn as non-guarding scatter-spawners, releasing eggs over the substrate without forming pairs or defending a nest site, and breeding of Microglanis species is only rarely attempted or achieved in home aquaria — this is a group known far better from imported wild fish than from captive spawns.
Breeding
Breeding is not documented as a routine event in the aquarium hobby for Microglanis cibelae. Where Microglanis species have spawned, the pattern reported for the genus is open scattering of eggs with no parental care afterward — the adults do not guard eggs or fry. Softer, slightly acidic water is suggested as more likely to encourage spawning condition than harder, more alkaline water, but detailed accounts of a successful home breeding of this particular species are lacking, so keepers should treat any spawning as opportunistic rather than something to plan around.
In the aquarium
At a genuine adult maximum of around 3 in, Microglanis cibelae is one of the smaller catfishes an aquarist can keep and suits a modestly sized tank, though it should still be given a sandy or fine-gravel bottom and plenty of cover — wood, rockwork or leaf litter — to retreat into during the day, since it is a nocturnal fish that hides until dusk. PlanetCatfish reports the genus as comfortable across roughly 72–82 °F and generally undemanding about water chemistry for day-to-day maintenance, even though breeding condition calls for softer, more acidic water.
Two care points follow directly from its biology: it is scaleless, so medicate conservatively, especially with copper-based treatments; and it carries locking dorsal and pectoral spines that can snag a net, so move it in a cup or container instead. Feed after lights-out to match its nocturnal habits, and keep tankmates modest in size and temperament — this is a peaceful scavenger, not a fish built to compete with boisterous or predatory companions.
Conservation
Microglanis cibelae has not been formally assessed by the IUCN Red List and currently carries a status of Not Evaluated. It is known only from a limited set of coastal drainages in Rio Grande do Sul and Santa Catarina, a heavily developed and agriculturally pressured part of southern Brazil, so its restricted range is a reason for caution even without a formal assessment.
The taxonomic uncertainty around its relationship to Microglanis cottoides also complicates any conservation picture, since population data gathered under one name may not cleanly separate from the other. As with many small, poorly studied South American catfishes, the honest summary is that too little is known to say more than "data sparse" about its true conservation status.