Taxonomy & naming
Centromochlus meridionalis was described in 2013 by Sarmento-Soares, Cabeceira, Carvalho, Zuanon and Akama, with the type locality in the Rio Teles Pires, a tributary of the Rio Tapajós in Mato Grosso State, Brazil. It belongs to the family Auchenipteridae, the driftwood catfishes, within the genus Centromochlus — a group of small South American catfishes closely tied to submerged wood and leaf litter.
As a recently described species, published detail on its relationships and full range remains limited, and data on some aspects of its biology is still sparse. The genus Centromochlus has been reshuffled over time as Auchenipteridae taxonomy has been revised; this account follows the current placement in Centromochlus.
Morphology
Centromochlus meridionalis is a genuinely small catfish, reaching a maximum of about 2.5 in standard length, with published measurements of adults ranging roughly 1.5–2.5 in SL. Like other driftwood cats it has a slender, tapering body, a flattened head, and long barbels used to feel out food and structure in low light.
As in virtually all catfishes its skin is naked and scaleless, which makes it more sensitive to certain medications than scaled fish. It carries the stiff, lockable pectoral spines typical of the family; these can snag in a soft net, so it is best scooped into a small container rather than netted directly.
Habitat
The species is known from first- and second-order streams in the Tapajós drainage of Mato Grosso, southern Brazilian Amazonia — small, clear-water streams with slow current, the kind of habitat where fallen wood and leaf packs accumulate along the margins and bottom.
Detailed water-chemistry data for this species has not been published, but a closely related congener, Centromochlus schultzi, is found in soft, acidic water around pH 5.0–7.0 at 72–82 °F, and this is a reasonable guide given the shared genus and similar southern-Amazon distribution. As with any data-sparse species, treat these as an informed estimate rather than a confirmed range for meridionalis itself.
Feeding
Driftwood catfishes are nocturnal benthic foragers. By day they hide among submerged wood, roots and leaf litter, emerging after dark to work the bottom and the wood surfaces for small invertebrates and detritus, often feeding head-down against the substrate.
In the aquarium this translates into a fish that does best on sinking pellets and small frozen foods offered after the lights go out, when it is not out-competed by more active daytime tankmates. Live or frozen bloodworm, brine shrimp and similar small foods suit its natural micro-predator diet.
Mating
Auchenipteridae are unusual among catfishes in using internal fertilisation. In males the anal fin is modified into an intromittent organ, and mating takes place internally rather than through the broadcast egg-and-sperm release typical of most catfish. Sperm is transferred in discrete bundles, and the female is able to store it and lay fertile eggs later, sometimes well after mating has taken place.
This reproductive mode has been documented across the driftwood catfish family, though the fine details for Centromochlus meridionalis specifically have not been published. It is a genuinely rare strategy among catfishes and worth stating plainly rather than assuming the open-water egg-scattering typical of most other groups.
Breeding
Because fertilisation is internal, with the female storing sperm and spawning at her own timing, driftwood catfishes are not bred in the aquarium in any documented, repeatable way, and this species is no exception — there is no aquarium breeding record for Centromochlus meridionalis. Parental care beyond egg-laying is not documented for the genus.
Given the internal-fertilisation strategy and the general absence of home-breeding reports across Centromochlus, aquarists should not expect to reproduce this species in a home tank; it remains, like most of its relatives, a wild-collected import.
In the aquarium
Centromochlus meridionalis stays small — around 2.5 in — so it suits a modest species or nano-community tank, but it should still be given driftwood, roots and leaf litter to mimic the stream-margin habitat it comes from, plus dim lighting and cover for daytime hiding. Its naked, scaleless skin means medications, especially copper-based treatments, should be dosed conservatively, as for loaches and other scaleless catfish.
Its locking pectoral spines make it worth moving in a container rather than a net. As a nocturnal micro-predator it is best fed sinking foods after lights-out, and given its tiny size it should only be kept with equally small, peaceful tankmates that will not outcompete or predate it.
Conservation
Centromochlus meridionalis has not been evaluated by the IUCN Red List. As a recently described species with a range so far documented only from streams of the Tapajós drainage in Mato Grosso, its broader distribution and population status are not well characterised.
Small-range Amazonian stream fishes like this one can be vulnerable to deforestation and habitat disturbance in their catchments, but without a formal assessment or detailed range data, its conservation status is best described as data-sparse rather than assumed safe.