Taxonomy & naming
Hoplisoma surinamense was described in 1970 by Han Nijssen, the Dutch ichthyologist whose monographic work on Surinamese and Guianan corys named a large fraction of the region's species. The epithet is geographic, for Suriname, where the type material was collected. The fish belongs to the family Callichthyidae, the armoured catfishes, in the subfamily Corydoradinae.
The long-overgrown genus Corydoras was revised in 2024 by Dias, Tencatt and colleagues, whose phylogenomic study split it among several resurrected genera. Under that scheme this short-snouted species moves into Hoplisoma — the largest of the new genera, gathering most of the deep-bodied, blunt-faced 'classic' corys — and takes the grammatically corrected combination Hoplisoma surinamense (the neuter genus requires the neuter ending). The recombination is recent and not yet universal; the hobby still says 'Hoplisoma surinamense', so we keep that heading while noting the current name.
This fish was long listed as Corydoras surinamensis; Eschmeyer's Catalog of Fishes places the species in Hoplisoma, and the current combination Hoplisoma surinamense is followed here.
Morphology
This is a small, short-snouted cory reaching about 2 in in standard length, built on the standard armoured plan: a deep, flat-bellied body clad in two overlapping rows of bony scutes meeting in a dorsal ridge, a blunt helmet of a head, and three pairs of barbels fringing the downturned mouth. The colour is a pale body patterned with dark spotting or blotching that tends to concentrate into a darker flank marking, with a dark band through the eye region and clear to lightly marked fins. The dorsal, pectoral and adipose fins each bear a stiff leading spine, the usual cory defence. Females grow larger and rounder than males, most obviously when carrying eggs.
Habitat
Hoplisoma surinamense is known from the Coppename River basin in Suriname, a clear-water river of the Guiana shield draining north to the Atlantic. This is a comparatively narrow, regionally restricted distribution rather than the continent-wide spread of the trade corys.
It is a benthic fish of quieter water — sandy and silty margins, pools and slow reaches with leaf litter and submerged wood over soft substrate it can sift. These are warm, soft, generally slightly acidic to neutral forest waters, broadly 72–77 °F with pH around 6.0 to neutral. Like all corys it is a facultative air-breather, surfacing to gulp air and absorb oxygen through a vascularised hindgut, which lets it cope with warm, sometimes oxygen-poor shallows.
Feeding
Hoplisoma surinamense is a benthic omnivore and detritivore. It works the bottom continuously, burying its snout and barbels in sand to taste out small invertebrates, insect larvae, worms, micro-crustaceans and organic detritus, expelling cleaned sand through the gills. In the aquarium it takes sinking pellets, frozen bloodworm and brine shrimp and other small foods; like all corys it should be offered a varied diet rather than left to subsist on what its tankmates drop.
Mating
Corys are egg-laying shoalers with no pair bond and a distinctive courtship. A ready female cleans a spawning site and the group becomes active; a male takes up the classic 'T-position' at right angles to her head, and she appears to take his milt into her mouth. Sperm is thought to pass rapidly through her gut to fertilise the few eggs held in a basket of her pelvic fins, which she carries to the cleaned surface and presses into place. The sequence repeats a few eggs at a time. Specific spawning observations for H. surinamense are scarce, but it is expected to follow this group-wide pattern.
Breeding
Little aquarium breeding data is published for Hoplisoma surinamense specifically. As a typical short-snouted Hoplisoma-group cory it is expected to spawn in the manner of the genus: a cooler, large water change imitating the rainy season triggers a group skewed toward more males than females, and adhesive eggs are laid in small batches on cleaned surfaces with no parental care — adults eat the eggs, so breeders remove eggs or parents. Eggs hatch in a few days and the fry take microworm, baby brine shrimp and powdered foods once the yolk is absorbed. Honest note: clutch size and reliable triggers for this particular species are not well documented.
In the aquarium
Hoplisoma surinamense is an infrequent import rather than a trade staple, but its care follows the cory rule book. It is a shoaling fish and must be kept in a group of six or more; alone or in pairs it is stressed and reclusive. Give a group a footprint of at least 23.6 in / 20 US gal, since bottom area matters more than height.
Substrate is not decoration: provide soft sand or very smooth, rounded fine gravel, never sharp or coarse gravel, which erodes and infects the barbels into the stubby faces that mark poor husbandry. Keep the bottom clean. Water should be warm but not hot (about 72–77 °F), well-filtered and well-oxygenated, changed regularly, and kept soft and slightly acidic to neutral to match its Guianan origin. It is peaceful and suits a quiet community of small tetras, pencilfish and dwarf cichlids. As with any cory, net spines catch easily (use a cup), and a badly distressed cory can release skin toxins that, in the confined volume of a transport bag, can kill the whole group — so handle and move them carefully.
Conservation
The IUCN Red List assesses Hoplisoma surinamense as Least Concern (assessed 2021). The Coppename basin lies partly within protected areas of Suriname's interior, a relatively well-conserved corner of Amazonia–Guiana, and no specific major threats to the species are identified. That said, a regionally restricted fish always carries more inherent risk than a continent-spanning one, and the broad pressures on Guianan freshwaters — mining (notably gold and its mercury pollution), deforestation and water-quality decline — bear watching even where a species is currently secure.