Taxonomy & naming
Microglanis lundbergi was described by Jarduli and Shibatta in 2013 in the Brazilian journal Neotropical Ichthyology, based on material collected from the rio Solimões — the Amazon's main channel — at Tefé, Amazonas State, Brazil. It belongs to the family Pseudopimelodidae, the bumblebee and dwarf pimelodid catfishes, a group only formally separated from the Pimelodidae in the early 2000s; older literature and some historical Microglanis records may still appear under the broader Pimelodidae. The Catalog of Fishes (Eschmeyer, California Academy of Sciences) is the authority for the current valid combination, Microglanis lundbergi, and no synonymy or reassignment is indicated in the sources consulted.
The genus name Microglanis combines the Greek mikros, "small", with glanis, an old name for a catfish — "small catfish", an apt description for a genus in which most species stay under a few centimetres. The species epithet lundbergi honours the American ichthyologist John G. Lundberg, a leading authority on Neotropical catfish systematics and coordinator of the Calhamazon project that surveyed Amazon basin fishes. Naming a new species after Lundberg is a nod to his broader contribution to understanding catfish diversity in the region rather than to any direct role in this description.
Morphology
Microglanis lundbergi is one of the smallest catfishes described from the Amazon: the holotype measured only 1 in standard length, with paratypes ranging from about 1 in SL — well under 1 in even at full size. Like other members of the genus it has the compact, big-headed, short-bodied build typical of bumblebee catfishes, with a flattened head, three pairs of sensory barbels, and an adipose fin set well back toward the tail.
As in essentially all catfishes, the skin carries no scales; Microglanis species instead rely on a mucus-covered, naked skin, which is a point to bear in mind for medication dosing (see "In the aquarium"). Fine details of colour pattern and fin-spine counts are the diagnostic features used to separate M. lundbergi from its many congeners, several of which are similarly tiny and superficially alike — a reminder that Microglanis is a genus better identified from formal keys and type material than from casual observation.
Habitat
The species is known from the rio Solimões — the name given to the Amazon's main channel above its confluence with the Rio Negro — at Tefé, in the Costa das Capivaras area of Amazonas State, Brazil. This makes it the first Microglanis recorded directly from the Amazon's white-water main channel rather than from one of the basin's countless smaller tributaries and floodplain habitats where most congeners are found.
The type locality is warm, white-water Amazon river habitat, with the holotype and paratypes collected from among organic matter and submerged wood along the channel margin. White-water Amazon rivers like the Solimões carry a heavy sediment load from Andean headwaters and are less acidic than the basin's clearwater and blackwater tributaries; specific temperature and pH figures for this species were not captured in the sources reviewed, and precise water chemistry should be treated as data sparse pending further study of the type locality.
Feeding
Microglanis lundbergi has not been the subject of dedicated dietary study, but its biology follows the pattern well documented across the genus: a nocturnal, benthic micro-predator and omnivore that forages over the bottom after dark for small invertebrates, detritus and other opportunistic food items, rather than actively hunting in open water during the day.
In aquarium accounts of Microglanis generally, captive fish accept standard dried and flake foods along with frozen foods such as bloodworm and brine shrimp, taking these most readily once the lights are off and the fish come out to forage. Given its very small adult size, any food offered would need to be correspondingly small — sinking micro-pellets, crushed flake or small frozen foods rather than anything sized for larger catfish.
Mating
No courtship or spawning behaviour has been documented for Microglanis lundbergi specifically. Across the genus Microglanis, aquarium breeding is only rarely reported, and detailed accounts of courtship in the wild or in captivity are scarce; where spawning has been observed in related bumblebee catfishes, fish are conditioned in soft, slightly acidic water and eggs are deposited among plants or other cover rather than through any elaborate pairing display.
Given the almost total absence of published data for this species, its natural mating behaviour should be treated as unknown rather than inferred from relatives.
Breeding
Breeding has not been documented for Microglanis lundbergi in the sources reviewed, and it should not be assumed to spawn like an open-water egg-scatterer or like the bubble-nesting armored catfishes — those modes belong to unrelated families. For the genus Microglanis as a whole, aquarium spawning is reported only rarely and is not a reliable, repeatable event in home tanks; where it has occurred, eggs are scattered onto plants in soft, slightly acidic water with no parental care of the brood.
In practice, Microglanis lundbergi should be considered essentially unbred in the aquarium at this time. Anyone acquiring this species is keeping a wild-type novelty rather than a captive-bred staple, and claims of successful home breeding for this exact species would need to be weighed carefully against the very thin published record.
In the aquarium
Microglanis lundbergi is vanishingly rare in the hobby and, at under 1 in adult length, is one of the smallest catfishes an aquarist could keep — this is a nano or species-tank fish, not a bioload-tolerant workhorse, and its tiny size means it can be out-competed or even eaten by larger tankmates. As with every catfish, the skin is naked and scaleless, which makes it more sensitive than scaled fish to copper-based medications and some other treatments; err toward conservative, half-strength dosing if treatment is ever needed.
Microglanis species are nocturnal and secretive, spending daylight hours tucked into wood, leaf litter or dense planting, so a tank furnished with plenty of low cover and subdued lighting suits them far better than an open aquascape. Given the paucity of specific husbandry data for this species, water should be kept warm and clean, mirroring general soft-water South American conditions, with feeding offered after dark to match its natural rhythm. Because published care information is so limited, this is a fish best suited to an experienced keeper willing to observe and adapt rather than follow an established recipe.
Conservation
The IUCN Red List lists Microglanis lundbergi as Data Deficient, reflecting how little is known about its distribution, population trend and threats beyond the original description from a single stretch of the rio Solimões at Tefé. A Data Deficient rating is not a clean bill of health — it means there simply is not enough information to assess extinction risk, not that the species is secure.
As with many recently described, narrow-range Amazonian catfishes, the main long-term concerns are the general pressures facing the Solimões/Amazon main channel and its floodplain habitats — sedimentation, water-quality changes and habitat disturbance tied to development along the river. There is no indication in the sources reviewed that M. lundbergi is targeted by the aquarium trade; its rarity in the hobby likely reflects its tiny size and narrow known range rather than any deliberate collection pressure.