Taxonomy & naming
Burgess's cory was described by Herbert R. Axelrod in 1987, in the hobbyist magazine Tropical Fish Hobbyist, from material taken in the Rio Unini — a tributary of the Rio Negro in Amazonas State, Brazil — which remains the type locality (holotype MZUSP 37692). Because the original description appeared in a popular magazine rather than a peer-reviewed journal, formal diagnostic detail has always been comparatively thin, and much of what is reliably known about the fish comes from later catalogues and the aquarium literature rather than the description itself.
It was placed, like almost all 'cory cats', in the enormous genus Corydoras Lacépède, 1803 (family Callichthyidae), and traded worldwide as Corydoras burgessi. That genus had swollen past 170 species and proved not to be a single natural lineage. In 2024 Dias, Tencatt and colleagues published a large phylogenetic revision of the Corydoradinae (DOI 10.1093/zoolinnean/zlae053) that split Corydoras into several genera — among them Brochis, Hoplisoma, Gastrodermus and Osteogaster — and under that scheme Burgess's cory becomes Hoplisoma burgessi, the combination now carried by Eschmeyer's Catalog of Fishes and FishBase. The change is recent and the hobby still overwhelmingly says 'Corydoras burgessi', so we keep that as the display heading while recording the current combination honestly. The species epithet honours Dr Warren E. Burgess, the American ichthyologist who co-authored the Colored Atlas of Miniature Catfish.
Morphology
This is a small, deep-bodied cory reaching only about 2 in; FishBase records a maximum of roughly 2 in standard length, and Seriously Fish gives 2 in. Like all Corydoras it wears armour rather than scales — two overlapping rows of bony plates (scutes) down each flank meeting in a dorsal ridge, a hard helmet of a head, and three pairs of barbels fringing the downturned mouth.
The colour pattern is what sets it apart. The body is high and pale — a clean ivory-to-white ground — and the fish carries a bold black 'saddle' or blanket beneath and into the dorsal fin, restricted to the area below the dorsal and running up into most of the fin itself, plus a dark blotch over the shoulder and a dark mask through the eye. On top of the head, just ahead of the dorsal saddle, sits a paler, yellowish patch. That combination of a high white body and the dorsal-restricted black mark is the most reliable way to separate it from its many look-alikes. The dorsal, pectoral and adipose fins each bear a stiff spine, and a careless hand can be jabbed by the locking pectoral spines.
Habitat
Corydoras burgessi appears to be endemic to the upper Rio Negro basin in Amazonas, Brazil, though detailed locality records are scarce; trade specimens are reportedly collected in the vicinity of São Gabriel da Cachoeira, which is also type locality for the similar C. adolfoi. This is classic Rio Negro blackwater country: pristine, tea-coloured tributaries and flooded-forest channels where the water is stained dark by dissolved tannins and humic acids leached from the forest floor.
Those are some of the softest, most acidic waters any cory occupies — very low conductivity, almost no measurable hardness, and a pH often in the range of 4.0 to 6.0. They are warm, shaded and nutrient-poor, carpeted with leaf litter and submerged wood, and shared with small characins, pencilfishes (Lebiasinidae) and dwarf cichlids of the genus Apistogramma. Like all corys it is a facultative air-breather, darting to the surface to gulp air and absorb oxygen through a modified, vascularised hindgut — a useful trick in the warm, oxygen-poor margins it frequents.
Feeding
Burgess's cory is a benthic, foraging omnivore. In its blackwater home it works the leaf litter and soft substrate, sifting sand and detritus through its barbels to extract small invertebrates, insect larvae, micro-crustaceans, worms and fallen organic matter, and expelling cleaned sand through the gills. The decomposing leaf litter of its habitat also fosters a film of microorganisms that feeds both adults and fry.
In the aquarium it readily takes sinking dried foods alongside small live and frozen items — bloodworm (chironomid larvae), Tubifex, Daphnia and the like — and a varied diet keeps it in condition and breeding trim. As with every cory, it should never be treated as a 'cleaner' left to scavenge leftovers; it needs food of its own that reaches the bottom.
Mating
Corydoras are egg-laying shoalers with no pair bond and the distinctive 'T-position' courtship shared across the genus. When a female is ripe she cleans a site and the group becomes active; a male aligns himself at right angles to her head, forming the classic T, and she appears to take his milt into her mouth. Sperm is thought to pass quickly through her gut to fertilise the few eggs she clasps in a basket formed by her pelvic fins, which she then carries to a chosen surface and presses into place. The sequence repeats, a few eggs at a time, until a modest clutch is distributed across the spawning sites. Aquarist accounts of C. burgessi note that females tend to scatter their eggs one or two at a time all around the tank, with a marked preference for fibrous surfaces — roots, spawning mops and Java moss — over the bare glass.
Breeding
Burgess's cory can be bred along the same lines as many of its relatives, though it is less prolific than the commercial workhorses. Breeders typically condition a group skewed toward males (around two males per female), then trigger spawning with a large, cooler water change of 50–70% that mimics the rainy season, raising oxygenation and flow, and repeat daily until the fish spawn. Clutches are small — hobbyist reports put them at roughly 10–20 eggs per spawn, laid in small batches at intervals of two to three weeks, sometimes prompted by cool changes or falling barometric pressure.
There is no parental care; adults will eat the eggs, so breeders either move the adhesive eggs (they can be rolled gently up the glass) or remove the parents, often adding methylene blue or alder cones to deter fungus. Incubation runs about three to four days, and once the fry absorb their yolk sacs they take microworm and Artemia nauplii. The fry are reported to grow quickly — reaching about 0.5 in in three weeks and looking like miniature adults at 1 in by ten weeks — and seem to do better over a thin layer of sand than on bare glass.
In the aquarium
This is a rewarding but slightly more demanding cory than the beginner staples, chiefly because of where it comes from. It is a shoaling fish and should be kept in a group of at least six (the bare minimum often quoted is four to six); a group is content in a tank of around 80 x 12 in footprint or equivalent, since bottom area matters far more than height.
Substrate is not negotiable: provide soft sand or very smooth, rounded fine gravel kept scrupulously clean, because corys feed by sifting and sharp or dirty substrate erodes and infects their barbels. Driftwood, dried leaf litter and gentle, well-oxygenated filtration suit it; an air-driven sponge filter is usually ample. While it tolerates a fairly broad envelope in captivity (roughly 68–82 °F, pH from acidic to neutral), it shows best and is likeliest to breed in soft, warm, slightly acidic, tannin-stained water that echoes its blackwater origins. It is utterly peaceful and an ideal companion for small characins, pencilfish, dwarf cichlids and other calm soft-water community fish. Two standard cory cautions apply: the fin spines can tangle in a net, so a cup is safer, and a badly stressed cory can release a skin toxin that, in the confined volume of a bag, can kill the whole group — so transport them with care.
Conservation
Corydoras burgessi is assessed by the IUCN as Least Concern (assessment dated 7 November 2018). The upper Rio Negro basin it inhabits is still largely intact, sparsely populated and relatively well-protected, and there is no evidence of a population decline. As a blackwater specialist with a comparatively restricted, single-basin range, however, it is more exposed than the continent-wide generalists: it depends on the particular chemistry of pristine tannin-stained water, so any large-scale deforestation, damming or pollution in the upper Negro would erode exactly the habitat it needs. Collection for the aquarium trade is modest given its relative scarcity in shops, and a precise picture of its abundance is limited by how few detailed field records exist for the species.