Taxonomy & naming
Centromochlus akwe was described in 2021 by Coelho, Chamon and Sarmento-Soares in the journal Zootaxa. It belongs to the family Auchenipteridae, the driftwood catfishes, within the order Siluriformes, and to the genus Centromochlus, a group of small South American catfishes historically lumped with the closely related genus Tatia.
The species epithet honours the Akwê, the self-designation of the Xerente people, an indigenous nation of the Tocantins River basin in Brazil, in recognition of the region where the fish occurs. It is diagnosed from its congeners chiefly by a vermiculated (worm-like patterned) dorsum — a trait shared with only a few other Centromochlus, namely T. brunnea, T. dunni and T. meridionalis — and by a pectoral-fin spine marked with alternating dark and light bars. It occurs sympatrically with the similar Centromochlus schultzi in the same stretch of river.
Morphology
Centromochlus akwe is a small catfish, reaching about 3 in standard length. As in other driftwood cats it has a scaleless, naked body, a somewhat flattened head, barbels around the mouth, and a stiff, serrated, locking pectoral-fin spine typical of catfishes generally — a feature that can snag a net and jab careless hands, so it is best scooped in a container rather than netted.
The diagnostic feature that separates it from most of its relatives is the vermiculated pattern across the dorsum — fine, worm-like markings rather than the plain, uniform colouring seen in most congeners — combined with alternating dark and light banding along the pectoral spine. Data on this recently described species remain sparse beyond the original description; detailed measurements of fin ray counts and other diagnostic characters are documented in the type description rather than summarised here.
Habitat
The species is known from the median portion of the Araguaia River, part of the larger Tocantins-Araguaia basin in Brazil, South America. Specimens have been collected from crevices within lateritic bedrock substrate overlain by alluvial sediment — a rocky, current-swept microhabitat rather than open sand or leaf litter.
Field collections found the fish in these rock crevices during both twilight and daytime hours, typically lethargic when found, consistent with a nocturnally active species sheltering by day. Specific water chemistry values for the type locality were not captured in available sources; as a tropical Brazilian river-crevice dweller it is reasonable to expect warm, well-oxygenated, flowing water, though exact temperature and pH data are sparse for this species specifically.
Feeding
As a driftwood catfish, Centromochlus akwe is best understood as a nocturnal benthic micro-predator and omnivore, foraging over and within its rocky crevice habitat mainly after dark for small invertebrates and other opportunistic food items — the pattern documented for the closely related and better-studied genus congener Centromochlus perugiae, which takes mosquito larvae and small invertebrates in the wild.
In the aquarium, related Centromochlus species accept sinking pellets and frozen foods readily once settled, and do best fed after lights-out so a shy, nocturnal fish is not out-competed by more active tankmates. Specific dietary data for C. akwe itself has not been published beyond this genus-level pattern.
Mating
Centromochlus akwe belongs to the Auchenipteridae, the driftwood catfish family, which is one of the few groups of catfish that does not spawn by simple egg-scattering. Instead, auchenipteroid males possess an intromittent organ formed from a modified anal fin, and fertilisation is internal: the male transfers sperm directly to the female during mating.
This is a genuinely unusual reproductive strategy among catfishes. Rather than fertilising eggs the moment they are released, the female is able to store sperm internally and lay fertile eggs some time after mating has taken place — a trait documented across the genus, including the well-studied congener Centromochlus perugiae. Species-specific observations of mating behaviour in C. akwe itself have not been published; the mechanism described here follows the family- and genus-level pattern.
Breeding
Following internal fertilisation, females of this genus are known to deposit fertile eggs into sheltered crevices — in the aquarium, small caves, bamboo tubes or short lengths of PVC pipe serve the same purpose as the natural rock crevices the wild fish is found in. Adequate water flow appears to support successful spawning in the related Centromochlus perugiae, and the same conditions likely apply here.
No published account describes captive breeding of Centromochlus akwe specifically, and given how recently it was described (2021), it has essentially no documented aquarium-breeding history. Parental care beyond egg deposition is not established for the species; keepers attempting to breed it should expect to draw on the wider genus's known biology rather than species-specific guidance.
In the aquarium
Centromochlus akwe stays small — to roughly 3 in standard length — but like its genus relatives it is a fish for a larger footprint than its size suggests: related Centromochlus species are recommended for aquaria with at least 15.5 in of frontage, clear water and shallow-to-strong current, furnished with bamboo or PVC tubes and dense vegetation to mimic the crevices it shelters in. It is a scaleless catfish, so it is more sensitive than scaled fishes to copper and many medications — dose conservatively. Its pectoral spine locks and can snag a net or jab a hand, so move it in a container rather than netting it directly.
As a nocturnal species it is most active after lights-out and appreciates dim daytime cover; feeding after dark helps it compete for food in a community setting. This species was only described in 2021 and is not established in the ornamental trade, so aquarium availability and detailed husbandry experience are both essentially undocumented; anyone keeping it would largely be extrapolating from better-known Centromochlus and Tatia species.
Conservation
The IUCN Red List has not evaluated Centromochlus akwe (Not Evaluated), which is unsurprising given the species was only formally described in 2021 and is known from a limited stretch of the median Araguaia River.
As a narrow-range endemic tied to a specific bedrock-crevice microhabitat within one river system, it is potentially vulnerable to changes in that habitat — sedimentation, damming or water-quality decline in the Araguaia basin — though no population trend or threat assessment has been published. Its conservation status should be treated as genuinely unknown rather than assumed safe.