Taxonomy & naming
Corydoras oxyrhynchus was described by the Dutch ichthyologists Han Nijssen and Isaäc Isbrücker in 1967, from Gojo Creek, a tributary of the Saramacca River in Brokopondo, Suriname — still the type locality. It was placed in Corydoras Lacépède, 1803 (family Callichthyidae). The epithet is built from the Greek oxys ('sharp') and rhynchos ('snout'), a direct reference to the conspicuously long, pointed snout that distinguishes it.
When Dias, Tencatt and colleagues revised the Corydoradinae in 2024 and divided the old omnibus Corydoras among several genera (Brochis, Hoplisoma, Gastrodermus, Osteogaster and others, alongside Aspidoras and Scleromystax), the name Corydoras was kept for the long-snouted, 'saddle-snouted' lineage that contains the genus type species, Corydoras geoffroy. As a long-snouted species, C. oxyrhynchus sits squarely within that restricted Corydoras and keeps its combination unchanged — Corydoras oxyrhynchus remains both the valid and the familiar name. Planet Catfish, FishBase and Corydoras World all continue to list it under Corydoras.
Morphology
This is a small to medium cory reaching about 2 in in standard length. Its defining feature is the snout: long, narrow and tapering to a point, far more drawn-out than in the blunt-headed corys, with three pairs of barbels at the downturned mouth. The body is otherwise the familiar Corydoras shape — short, deep and flat-bellied with an arched back — armoured by two rows of overlapping bony scutes that meet along the dorsal ridge, the head a hard helmet of bone.
The colour is restrained: a pale to greyish-tan ground with subtle darker mottling and, in many fish, a faint band along the upper flank. The fins are largely clear. As in all Corydoras, the dorsal and pectoral fins each begin in a stiff, mildly venomous spine. Females grow larger and rounder-bodied than males, while mature males tend to develop more pointed fin tips — differences most easily judged by viewing the fish from above.
Habitat
Corydoras oxyrhynchus is native to the coastal rivers of the Guianas, specifically the Saramacca River drainage in Suriname, with records extending into the wider Guyana waters. It is a fish of quieter, shallow water — the sandy margins of creeks and rivers, backwaters and shaded edges, over soft sand and fine substrate with leaf litter, submerged wood and overhanging cover.
These are warm tropical waters, typically around 72–79 °F, ranging from acidic to slightly alkaline (about pH 6.0–8.0) and from soft to moderately hard. As a callichthyid it is a facultative air-breather, darting to the surface to gulp atmospheric air and absorbing oxygen through a vascularised region of the hindgut — the adaptation that lets corys persist in the warm, oxygen-poor shallows they favour.
Feeding
The sharpnosed cory is a benthic omnivore and detritivore, and its long snout is a specialised foraging tool, letting it probe deeper into sand and leaf litter than the blunt-headed species as it tastes out small invertebrates, insect larvae, worms, micro-crustaceans and organic detritus, venting cleaned substrate through the gills. In the aquarium it readily takes all prepared foods that reach the bottom — tablets, granules and larger sinking flake — as well as live and frozen foods such as bloodworm, whiteworm, grindal worm, Daphnia and Tubifex, which are also useful for conditioning a group toward spawning.
Mating
As in other Corydoras, this is an egg-laying shoaler with no pair bond and the genus's classic 'T-position' courtship. A ready female cleans a site, and as the group becomes active a male aligns at right angles to her head; she appears to take milt directly, the sperm passing rapidly to fertilise the one to few eggs she cups in a basket formed by her pelvic fins. She then carries those eggs to a chosen surface and presses them into place, the sequence repeating a few eggs at a time. No specific spawning account is documented for this species, but it is expected to follow the standard corydoradine pattern.
Breeding
There is no published captive-breeding report for Corydoras oxyrhynchus, but its reproduction should follow the usual Corydoras template. A group conditioned on varied live, frozen and dried foods and skewed toward more males than females is typically brought into spawning by a large, cool water change with increased oxygenation and flow, mimicking the rainy season and repeated until the fish spawn. The adhesive eggs, laid in small batches and stuck to glass, wood or plants, receive no parental care and will be eaten by the adults, so the breeder removes either the eggs or the parents. By analogy with related species, eggs should hatch in roughly three to five days, the fry taking microworm and baby brine shrimp once the yolk sac is absorbed.
In the aquarium
The sharpnosed cory is a peaceful, shoaling community fish that needs the standard cory care. Keep it in a group of at least six, in which it is far more confident and active; provide a tank with plenty of open bottom area rather than emphasising height.
Substrate is the key requirement: use a bed of soft, fine sand, or smooth rounded gravel as an imperfect alternative, and never sharp or chipped gravel, which abrades and infects the barbels and damages a dedicated long-snouted sifter especially badly. Border the open feeding area with driftwood and plants, and provide shade from bogwood, rockwork or floating plants. Keep the water warm (about 72–79 °F), clean, well-filtered and well-oxygenated, with a gentle current and regular changes; it tolerates a broad pH and hardness range. It is an excellent companion for small characins, rasboras, pencilfish, dwarf cichlids and other calm fish, and should not be housed with large or aggressive tankmates. Handle it gently, as the fin spines snag in nets and a stressed cory can release a skin toxin dangerous in the small volume of a transport bag.
Conservation
Corydoras oxyrhynchus is assessed by the IUCN Red List as Least Concern, last evaluated in 2021. It occupies the coastal rivers of the Guianas, where freshwater habitats remain comparatively intact and human pressures are lower than in much of South America, and it faces no specific species-level threat. As everywhere, deforestation, mining (including gold mining and its mercury pollution in the Guianas), agriculture and habitat alteration are background concerns for the shallow waters it favours, but the species as a whole is not considered at risk, and it is only modestly collected for the trade.