Taxonomy & naming
Centromochlus britskii was described by Sarmento-Soares & Birindelli in 2015. It belongs to the family Auchenipteridae, the driftwood catfishes, a mostly South American group of roughly 125 species in about 22 genera. The genus Centromochlus contains a number of small, similarly built driftwood cats, including C. perugiae, C. heckelii, C. orca, C. musaicus and C. reticulatus.
The species epithet honours Dr. Heraldo Antonio Britski, the Brazilian ichthyologist who collected the type material — a common practice in Neotropical catfish taxonomy, where new species are frequently named for the collectors and researchers who helped bring them to light. As with much of Siluriformes, the driftwood catfishes have been repeatedly reshuffled by revision; the Catalog of Fishes is the reference for the currently valid combination, and Centromochlus britskii is treated as valid under that genus.
Morphology
This is a genuinely small catfish: FishBase records a maximum size of just 1.5 in SL for both males and unsexed individuals, with sexual maturity reached at around 1.5 in SL. Like other Centromochlus it lacks an adipose fin, has a single dorsal spine with a serrated anterior margin followed by five soft rays, ten anal soft rays, and 32–33 vertebrae. Two pairs of mental barbels sit on the chin, typical of the genus.
As in essentially all catfish, the skin is scaleless (naked), which matters directly for aquarium medication — see "In the aquarium" below. The dorsal spine's serrations are a smaller-scale version of the locking, netting-snagging spines found across the driftwood catfish family; handle this species with the same care as its larger relatives even though it is tiny.
Habitat
Centromochlus britskii is known from the Rio Paraná basin in Brazil, where it occupies rocky, fast-flowing sections of the upper main channel, including habitat near cofferdams. It is a demersal species — a bottom-dweller — living in and around rock crevices in current rather than in slack backwaters.
As a tropical freshwater river fish of a fast, rocky channel, it experiences well-oxygenated, flowing water rather than the still, leaf-litter blackwater typical of many small Amazonian catfish. Detailed water-chemistry data for the type locality was not captured in available sources, so specific pH and hardness figures are not given here rather than guessed.
Feeding
FishBase describes C. britskii as carnivorous, with gut-content analysis showing chironomid (non-biting midge) larvae and other invertebrate fragments. This fits the broader pattern for driftwood catfishes: nocturnal benthic micro-predators that forage over and among rocks after dark for small invertebrates.
In the aquarium, related small Centromochlus species take standard sinking foods — small pellets, frozen bloodworm and brine shrimp, and other prepared foods — once acclimated. Because the genus is night-active, offering food after lights-out is likely to get better results than daytime feeding, and prevents this small fish being out-competed by bolder tankmates.
Mating
Centromochlus britskii belongs to Auchenipteridae, the only catfish family known to fertilise internally. The male's anal fin is modified into an intromittent organ that delivers sperm packets directly to the female. Rather than fertilising eggs externally at the moment of spawning, the female stores the sperm in an oviductal sac, along with her own mature unfertilised eggs, for a period afterward.
Days after mating, the female deposits a clutch — around 100 eggs in studied relatives such as Trachelyopterus galeatus — into a small cave or crevice, where the eggs are fertilised from the stored sperm as they are laid. This decoupling of mating from egg-laying is rare among catfish and worth stating plainly: it is not open-water egg-scattering, and it is not a bubble-nest species.
Breeding
Breeding follows directly from the family's internal-fertilisation strategy: after internal mating, the female stores sperm and lays a small clutch of fertile eggs in a rock crevice or cave days later, and in documented relatives the female guards the eggs until they hatch (roughly 4–5 days). No parental care has been documented from the male's side once the eggs are deposited.
No aquarium spawning has been documented specifically for Centromochlus britskii, and it does not appear to be an established captive-bred species in the trade. Given its rarity in the hobby and the specialised, internally-fertilised reproductive mode shared across the family, breeding it in a home aquarium should be considered unlikely rather than a realistic goal.
In the aquarium
This is a genuinely small catfish — under 1.5 in SL as an adult — so it does not present the size trap that catches out keepers of larger driftwood cats and other Siluriformes; a compact aquarium can suit it. It is, however, essentially unknown in the hobby: there is no dedicated profile for it on the major catfish reference sites, and it should be treated as a rare, likely wild-collected fish rather than a routine livestock item if it is ever offered for sale.
Two care points apply regardless of rarity. First, like all catfish it is scaleless, so it is more sensitive than scaled fish to copper and many medications — dose conservatively. Second, although its spines are small, they follow the same serrated, locking design as its relatives and can snag in a soft aquarium net; moving it in a container rather than netting it is the safer approach. Expect a nocturnal fish that wants rock crevices and cover for the day, emerging to forage after dark, and provide the flowing, well-oxygenated water typical of its rocky river habitat.
Conservation
Centromochlus britskii has not been evaluated by the IUCN Red List (Not Evaluated). This is typical for small, recently described, geographically restricted Neotropical catfishes that see little or no targeted conservation assessment.
Its known range in the upper Rio Paraná basin is a heavily developed river system with extensive damming and cofferdam construction — the same rocky, fast-flowing habitat the species occupies near cofferdams. As with many obscure single-basin catfish, the lack of a formal assessment reflects data scarcity rather than confirmed security, and hydrological changes to the upper Paraná are a plausible long-term pressure worth flagging even without a formal status.