Taxonomy & naming
Cope's cory was described in 1986 by Han Nijssen and Isaäc Isbrücker, the prolific Dutch students of the Corydoradinae, from the Río Pastaza drainage of the upper Amazon in Peru. It honours Edward Drinker Cope (1840–1897), the American palaeontologist and ichthyologist who described many South American fishes — hence copei, 'of Cope'. For decades it sat in the vast genus Corydoras Lacépède, 1803 (family Callichthyidae).
The 2024 revision of the subfamily by Dias, Tencatt and colleagues split that overgrown genus into several lineages, and under that scheme C. copei falls into the resurrected genus Hoplisoma Agassiz, 1846 — the lineage that takes in a large share of the spotted and saddle-patterned 'Corydoras' of the hobby. Eschmeyer's Catalog of Fishes and FishBase now carry the combination Hoplisoma copei, and we note that here while keeping the familiar Corydoras heading the trade still uses. The species is genuinely obscure: even modern profiles note that good diagnostic descriptions and reliable trade material are scarce, and it is easily confused with relatives such as C. acrensis.
Morphology
Cope's cory is a small species, reaching only about 2 in standard length, with the usual corydoradine build: a deep, plated body, two rows of overlapping bony scutes along each flank, a blunt armoured head and three pairs of barbels around the downturned mouth. Its colour is the spotted-to-marbled pattern common among the western-Amazon corys, and it is similar enough to several congeners — C. acrensis and others — that reliable identification really needs the original description rather than the eye alone.
As in all members of the subfamily, the dorsal and pectoral fins carry stiff spines, mildly venomous and prone to catching in a net. Beyond these general traits, fine morphological detail for the species is sparse in the accessible literature, a reflection of how little it has been studied since its description.
Habitat
Corydoras copei is a fish of the western Amazon headwaters in Peru, associated with the Río Pastaza drainage and possibly the lower Marañón — the lowland and foothill streams where the Andes give way to the Amazon basin. These are warm, soft-water habitats: clear to lightly stained streams and creeks over sand and leaf litter, fringed by rainforest.
Reported aquarium parameters fit that picture — temperatures around 68–79 °F, an acidic pH of roughly 5.0–7.0, and soft water. Like other corys it is a bottom-dweller of quieter margins and slow reaches rather than fast current, and as a facultative air-breather it can gulp atmospheric oxygen in the warm, low-oxygen pools that form in such habitats during the dry season.
Feeding
As a corydoradine, Cope's cory is a benthic foraging omnivore. It works the bottom of its home streams, sifting sand and litter with its barbels to find small invertebrates, insect larvae, worms and organic detritus. In aquaria — where it appears only occasionally — it takes the usual small foods: sinking dried pellets and tablets, frozen and live bloodworm, Tubifex and brine shrimp. A varied diet suits it, as it does all corys, and its small size calls for correspondingly small items.
Mating
No detailed account of spawning exists for C. copei specifically, but it is expected to reproduce in the manner universal to the Corydoradinae: an egg-laying shoaler with no pair bond, in which a ready female cleans a site, the group becomes active, and a male adopts the 'T-position' at right angles to her head. The female carries a few eggs at a time in a pelvic-fin basket and presses them onto the cleaned surface, repeating until a scatter of adhesive eggs has been laid. This description is drawn from the group rather than from observation of this little-studied species.
Breeding
Captive breeding of Cope's cory is essentially unrecorded; it is a rare import and not commercially produced. By analogy with related soft-water corys, spawning would be prompted by soft, acidic water and a cooler, rain-simulating water change, yielding small clutches of adhesive eggs laid on plants, wood and glass with no parental care — the adults will eat the eggs, so a breeder would separate them. Eggs of comparable species hatch in a few days and the fry take microworm and baby brine shrimp once free-swimming. Specific figures for clutch size and timing are not available for this species, so these are expectations from its relatives rather than measured data.
In the aquarium
Corydoras copei is firmly a specialist's fish — seldom seen, thinly documented, and most likely wild-caught when it does appear. Its care follows standard cory practice: keep it as a shoal of six or more, over soft sand that protects its barbels, in clean, gently moving, well-oxygenated water.
Reflecting its western-Amazon origin, it does best in soft, acidic to neutral water in the 72–79 °F range, ideally with some tannin staining from leaf litter. It is peaceful and belongs in a quiet community of small, soft-water South American fishes — small tetras, pencilfish, dwarf cichlids — rather than with boisterous tankmates that would outcompete so retiring a fish. As with all corys, lift it with a cup rather than a net to avoid snagging the fin spines, and transport it carefully, since a stressed cory can release skin toxins in the confined volume of a bag.
Conservation
Corydoras copei is assessed by the IUCN Red List as Least Concern. It is a western-Amazon species whose streams largely lie within still-forested parts of the Peruvian Amazon, and there is no evidence of any specific threat to it. That said, the assessment rests on limited information for a poorly known fish, and the broad pressures on Amazonian headwaters — deforestation, agriculture, and the mercury pollution from regional gold-mining — degrade exactly the kind of soft-water creeks it inhabits. Its obscurity means any change in its status could easily go unnoticed.