Taxonomy & naming
Hoplisoma sipaliwini was described by the Dutch ichthyologist Jan Hoedeman in 1965, on material from the Sipaliwini River in the Corantijn (Courantyne) drainage of Suriname — the river that also gives the species its name. It was placed in Corydoras Lacépède, 1803, the very large genus of South American armoured catfishes (family Callichthyidae) that for most of the twentieth century absorbed almost every 'cory cat' of the hobby.
That genus proved not to be a single natural lineage. In 2024 Dias, Tencatt and colleagues published a phylogeny-driven revision of the Corydoradinae that split Corydoras into several genera, reviving older names — among them Brochis, Hoplisoma, Gastrodermus and Osteogaster. Under that scheme H. sipaliwini falls in the resurrected genus Hoplisoma, and FishBase and the specialist literature now list it as Hoplisoma sipaliwini. The combination is recent and not yet universal in the aquarium trade, where the fish is still bought and sold as 'Hoplisoma sipaliwini' (and earlier as the collection code CW114), so we keep that hobby-familiar heading while recording the current placement here.
This fish was long listed as Corydoras sipaliwini; Eschmeyer's Catalog of Fishes places the species in Hoplisoma, and the current combination Hoplisoma sipaliwini is followed here.
Morphology
This is a small cory, reaching only about 1.8 in in standard length, with the usual compact, deep-bodied build of the group: a hard, blunt, helmet-like head, a downturned mouth fringed with three pairs of sensory barbels, and two rows of overlapping bony plates (scutes) armouring each flank in place of scales. The dorsal, pectoral and adipose fins each carry a stiff leading spine.
The colour pattern is a pale ground densely peppered with small dark spots over the body, with a characteristic dark marking on the dorsal fin and spotting that continues onto the tail. As with most corys the females grow a little larger and become noticeably broader and deeper-bodied than males when in spawning condition. Precise meristic and colour detail is best taken from Hoedeman's original description and later Guiana-Shield revisions rather than from the variable trade fish, since several similar spotted corys share the same coastal drainages.
Habitat
Hoplisoma sipaliwini is a Guiana-Shield endemic, recorded from the coastal river basins of Guyana and Suriname, with the type series from the Sipaliwini River in the Corantijn system. Like its relatives it is a fish of flowing fresh water — the sandy-bottomed creeks and river margins of the shield, typically clear to lightly tea-stained, soft and acidic.
FishBase records it as a benthopelagic tropical freshwater fish that is a facultative air-breather: in common with all corys it can gulp atmospheric air at the surface and absorb oxygen through a vascularised, modified hindgut, an adaptation that lets it cope with the warm, oxygen-poor pools of the dry season. Specific published temperature, pH and depth figures for wild populations are sparse; aquarium practice follows the general envelope for soft-water Guiana corys.
Feeding
Like other Corydoradinae, H. sipaliwini is a benthic omnivore and detritivore. It feeds by nosing into soft sand, taking small invertebrates, insect larvae, micro-crustaceans, worms and the organic film of detritus, and expelling cleaned sand through the gill openings as it sifts. It is an opportunist, not a specialist, which is part of why the group adapts so readily to captivity. In the aquarium it accepts sinking pellets and tablets, frozen bloodworm and brine shrimp, and other small prepared foods taken from the bottom.
Mating
No spawning account specific to H. sipaliwini has been widely published, but it can be expected to follow the well-documented corydoradine pattern. These are egg-laying shoalers with no pair bond: a ready female cleans a site, the group becomes active, and a male takes up the classic 'T-position' at right angles to her head. She appears to take milt into her mouth, sperm passes quickly through the gut to fertilise the few eggs she carries in a basket formed by her clasped pelvic fins, and she presses those eggs onto the cleaned surface. The sequence repeats a few eggs at a time until the clutch is laid.
Breeding
Captive breeding of H. sipaliwini is not yet commonplace, and there is no large body of published fry data for the species specifically. By analogy with related Guiana-Shield corys, spawning would be expected to follow a cool, soft water change that mimics the rains, with a small clutch of adhesive eggs scattered on plants, wood and glass and given no parental care — the adults will eat the eggs, so a breeder removes either the eggs or the parents. Eggs of similar corys hatch in roughly three to five days, and the fry take microworm, baby brine shrimp and fine prepared foods once the yolk sac is absorbed.
In the aquarium
H. sipaliwini is a peaceful, small shoaling catfish best kept in a group of six or more; kept singly or in pairs it is stressed and inactive. A modest tank with a generous footprint suits it better than a tall one, since bottom area matters most. The single most important detail is the substrate: provide soft sand or very smooth, rounded fine gravel, because corys feed by sifting and sharp or coarse grit erodes and infects their barbels, leaving them stubby and blunted — a common sign of poor husbandry.
Coming from soft, flowing shield waters, it is best given clean, well-oxygenated water on the soft and slightly acidic side, with gentle current and regular water changes. It makes an ideal companion for small tetras, pencilfish, rasboras and dwarf cichlids, and should never be housed with fish large enough to bully it. Two standing cautions apply to all corys: the fin spines can catch in a net, so a cup is safer for moving them, and a badly stressed cory can release a skin toxin that, in the small volume of a bag or bucket, may kill the whole group — so transport them carefully.
Conservation
Hoplisoma sipaliwini is assessed by the IUCN as Least Concern (assessment published in 2021). It occupies the relatively intact coastal drainages of the Guiana Shield, where freshwater habitats remain in comparatively good condition, and no major range-wide threat has been identified. As with all narrowly distributed shield endemics, localised pressures — gold-mining sedimentation, deforestation and pollution of small creeks — could affect particular populations, so the species' favourable status should not be read as immunity to habitat degradation.