Taxonomy & naming
Tatia jaracatia was described in 2009 by the Brazilian ichthyologists Carla Simone Pavanelli and Mauricio Bifi. It belongs to the family Auchenipteridae, the driftwood catfishes, and to the genus Tatia, a group of small, laterally compressed South American catfishes distributed across the Amazon, Orinoco and Paraná–Paraguay drainages. The Catalog of Fishes treats Tatia jaracatia as the valid name, and no earlier combination under another genus is on record — it was described directly into Tatia.
The species epithet jaracatia refers to its type locality, the rio Jaracatiá, a tributary stream of the lower rio Iguaçu basin in Paraná State, southern Brazil — the same drainage famous for the Iguazu Falls. As with many recently described small catfishes, Tatia jaracatia is best distinguished from its congeners by fine details of body proportions, fin-ray counts and colour pattern rather than by any single obvious feature, and it can be confused with other small Tatia species and with its close relative Centromochlus, which shares the driftwood-cat reproductive biology.
Morphology
Tatia jaracatia is a small, elongate, laterally compressed catfish, reaching only about 2.5 in standard length in males, among the smaller members of the driftwood catfish family. Like all Auchenipteridae it has a naked, scaleless skin — there is no bony armour, only bare skin — which makes it noticeably more sensitive to copper and many other medications than a scaled fish.
It carries three pairs of barbels around the mouth and a well-developed adipose fin typical of the family. As in other catfishes, the dorsal and pectoral fins carry stiff, serrated spines that can be locked erect; these snag readily in an aquarium net and can jab careless hands, so the fish is best moved in a container rather than netted. In mature males the first anal-fin ray is modified into a thickened, hook-like intromittent organ used to transfer sperm internally to the female — the clearest external sign of the family's unusual mating system.
Habitat
Tatia jaracatia is known from the rio Jaracatiá and other streams of the lower rio Iguaçu basin in Paraná State, Brazil, a drainage that empties over the Iguazu Falls into the Paraná River near the Brazil–Argentina–Paraguay border. The region's streams run clear and relatively fast over rock and sand substrates, with driftwood, submerged roots and leaf litter providing daytime shelter for a fish that is active mainly after dark.
Water in this part of the lower Iguaçu system tends toward soft and mildly acidic to near-neutral, and reported field conditions for the area put temperatures around 79 °F and pH near 6.1–6.5. Provide dense cover — driftwood, root tangles and leaf litter — to replicate the shaded, structure-rich margins this catfish uses by day.
Feeding
Tatia jaracatia is a nocturnal benthic omnivore, foraging over the bottom mainly after dark for small aquatic invertebrates, insect larvae and detritus, in keeping with the general pattern for small driftwood cats and their close relatives such as Tatia reticulata (formerly placed in Centromochlus).
In the aquarium it takes sinking pellets, frozen foods such as bloodworm and brine shrimp, and other prepared foods readily once settled, but because it feeds by night it is easily out-competed by diurnal tankmates. Offering food after lights-out, or ensuring it has undisturbed access to sinking food near its driftwood retreat, helps this shy species get its share.
Mating
Tatia jaracatia mates by internal fertilisation, the defining reproductive trait of the driftwood catfish family Auchenipteridae. The male's first anal-fin ray is modified into a rigid, hook-shaped intromittent organ that is used to transfer sperm directly into the female during a brief mating contact, rather than the pair simply shedding eggs and milt into open water.
Unusually among fishes, the female then stores the sperm internally and can go on to lay fertile eggs some time after mating has occurred, rather than spawning immediately. This decouples mating from egg-laying and is documented for the family in relatives such as Trachelyopterus galeatus; it is presumed to apply to Tatia jaracatia as a fellow auchenipterid, though the species has not been the subject of dedicated captive-breeding study.
Breeding
Because of its internal-fertilisation strategy, Tatia jaracatia does not fit the open-water egg-scattering pattern common to many catfishes, and there is no documented account of it being bred in home aquaria. The mechanics known for the family — internal mating followed by delayed, sperm-stored egg-laying by the female — make captive spawning difficult to trigger or predict, and beyond mating there is no evidence of parental guarding of eggs or fry in this species.
Given how little is published specifically on Tatia jaracatia's reproduction, hobbyists should treat it as essentially not bred in captivity at present; any aquarium stock is very likely wild-collected from its native Paraná State streams rather than farm-raised.
In the aquarium
Tatia jaracatia stays small — to about 2.5 in — but it is a nocturnal, cover-dependent fish rather than an easy, out-in-the-open community catfish, so a modest tank furnished with driftwood, roots and shaded hiding spots suits it far better than an open, brightly lit setup. Match its native lower Iguaçu conditions with soft, mildly acidic to near-neutral water around 79 °F and subdued lighting.
As a naked-skinned catfish it is medication-sensitive; dose copper-based treatments and many other medications conservatively, as with loaches and other scaleless fishes. Its dorsal and pectoral spines can lock and snag in a net, so move it in a cup or container instead. Feed after lights-out so this shy, mainly nocturnal species is not out-competed by more active tankmates, and keep it with peaceful, similarly sized fish given its small adult size.
Conservation
The IUCN Red List assesses Tatia jaracatia as Least Concern. It is known from the lower rio Iguaçu basin in Paraná State, Brazil, a drainage that has faced substantial hydroelectric damming, deforestation and water-quality pressure elsewhere along its length, though the species is not currently flagged as threatened.
As a recently described species with a comparatively restricted known range, its status would benefit from continued monitoring as the lower Iguaçu basin faces ongoing development pressure; specific population trend data for Tatia jaracatia itself is sparse.