Taxonomy & naming
Corydoras bifasciatus was described by the Dutch ichthyologist Han Nijssen in 1972, in the Netherlands Journal of Zoology, from material taken in a creek on the left bank of the Rio Cururu, a tributary of the upper Rio Tapajós near Maloca do Conzale, in Pará State, Brazil — still the type locality. The epithet bifasciatus is Latin for 'two-banded', for the paired dark stripes along the body.
For half a century it sat in the catch-all genus Corydoras Lacépède, 1803, the vast assemblage of South American armoured catfishes. That genus had become a taxonomic holding pen of more than 170 species and was demonstrably not a single natural lineage. In 2024 Dias, Tencatt and colleagues published a phylogenetic revision (Zoological Journal of the Linnean Society) that split it into several genera. Eschmeyer's Catalog of Fishes now lists this species as valid as Brochis bifasciata (Nijssen 1972) — a slightly unexpected placement, since Brochis is the lineage of the familiar broad, deep-bodied emerald and green corys rather than the slim striped forms one might guess from its appearance. The aquarium trade still overwhelmingly writes 'Corydoras bifasciatus', so we keep that as the heading while recording the current combination.
Morphology
This is a small cory, reaching roughly 2 in in standard length (about 2 in SL is the recorded maximum). The body is the typical Corydoradinae build — compact and armoured, with two rows of overlapping bony scutes down each flank rather than scales, a blunt helmeted head, and three pairs of barbels fringing the downturned mouth for sifting the substrate.
The defining feature is the colour pattern: a pale ground crossed by two dark longitudinal bands, one running mid-flank from behind the gill cover toward the tail base and a second, often fainter, lower band, the two giving the fish its name and separating it from the many other striped corys of the region. As in all the subfamily, the dorsal and pectoral fins are armed with stiff leading spines. Like its broad-bodied Brochis relatives it has a relatively deep, robust trunk.
Habitat
Corydoras bifasciatus is endemic to the upper Tapajós system of central Brazilian Amazonia, with FishBase placing it more broadly in the lower Amazon River basin; the type series came from a small clearwater creek feeding the Rio Cururu. These are warm, soft, often clear or tea-stained forest waters typical of the Brazilian Shield tributaries — shallow margins over sand and leaf litter, with submerged wood and gentle flow.
No dedicated study of its ecology has been published, so its preferences are inferred from the genus and from its collection sites: temperatures around 72–79 °F, acidic to near-neutral water (pH roughly 6.0–8.0) and soft to moderately hard conditions. Like other Corydoradinae it is a facultative air-breather, gulping atmospheric oxygen at the surface and absorbing it through a vascularised hindgut, an adaptation suited to warm, oxygen-poor shallows.
Feeding
There is no published diet study for this species, but it is a benthic omnivore in the mould of all corys. It feeds by nosing through soft sediment, using its barbels to taste out small invertebrates, insect larvae, micro-crustaceans, worms, fallen organic matter and biofilm, sieving mouthfuls of sand and expelling the cleaned grains through the gill openings. In captivity such fish take sinking prepared foods, frozen bloodworm and brine shrimp, and small live foods, foraging continuously over the bottom.
Mating
Spawning behaviour has not been documented for Corydoras bifasciatus specifically, but Corydoradinae share a stereotyped, well-studied courtship and there is no reason to expect this species differs. The fish are egg-laying shoalers with no pair bond. A receptive female cleans a spawning surface, and a male takes up the classic 'T-position' at right angles to her head; she appears to take milt into her mouth, which passes through the gut to fertilise the few eggs she cradles in a pelvic-fin 'basket' and then presses onto the cleaned site. The sequence repeats a few eggs at a time until the clutch is complete.
Breeding
No aquarium breeding account exists for this scarce species, so any reproductive detail is extrapolated from its relatives. Corydoradinae typically lay adhesive eggs in small batches on cleaned surfaces, often triggered by a cool, large water change mimicking the onset of the rainy season. They give no parental care and will eat their own eggs, so breeders of related corys remove either the eggs or the adults; eggs generally hatch in three to five days, and the fry take microworm, baby brine shrimp and powdered foods once the yolk is absorbed. Whether C. bifasciatus has ever been bred deliberately in numbers is not on record.
In the aquarium
Corydoras bifasciatus is rare in the trade and seldom kept, so detailed husbandry experience is thin; the sensible approach is to treat it as a typical small Amazonian cory. It is a shoaling fish and should be kept in a group of six or more, over soft sand or very smooth, rounded fine gravel — coarse or sharp substrate erodes and infects the barbels corys depend on, a common avoidable injury. Provide warm, well-filtered, well-oxygenated water (about 72–79 °F), soft and slightly acidic to neutral, with leaf litter and wood for cover and a gentle current. It is a peaceful community fish best matched with small, calm tankmates such as tetras and pencilfish. The usual cautions apply: the stiff fin spines can snag in nets, so a cup is safer for moving them.
Conservation
The IUCN Red List assesses this species (as Corydoras bifasciatus) as Least Concern, evaluated in 2018. The assessment reflects a reasonably wide occurrence in the Tapajós and lower Amazon drainage and the absence of evidence for major decline rather than detailed population data. The Tapajós basin faces real and growing pressures — hydroelectric damming, deforestation, gold-mining sedimentation and mercury contamination among them — that degrade the clearwater tributaries this fish inhabits, so its Least Concern status should be read as 'no evidence of trouble yet' rather than a guarantee of security.