Taxonomy & naming
Corydoras maculifer was described in 1971 by the Dutch ichthyologists Han Nijssen and Isaäc Isbrücker, from the Sangadinha (Sangadina) stream near Xavantina, a tributary of the rio das Mortes in the upper rio Araguaia basin of Mato Grosso, Brazil. The specific epithet maculifer means 'spot-bearing,' for the rows of dark blotches that cover the body. It is one of several similarly patterned spotted corys native to the middle and upper Araguaia and its great tributary the rio das Mortes.
The genus Corydoras Lacépède, 1803 (family Callichthyidae) had swollen to well over 170 species and was shown by molecular work not to be a single natural lineage. The 2024 revision by Dias, Tencatt and colleagues split it into several genera — Brochis, Hoplisoma, Gastrodermus, Osteogaster and a restricted Corydoras (sensu stricto) — and this species is retained within Corydoras in the strict sense, so the name is unchanged: Corydoras maculifer remains Corydoras maculifer. The Catalog of Fishes (Eschmeyer, CAS) lists it as a valid species.
Morphology
This is a medium-sized cory, reaching about 2–2.5 in in standard length — among the larger spotted species of its region. It has the standard armoured Corydoras build: two rows of overlapping bony plates down each flank, a hard helmeted head, a downturned mouth with three pairs of barbels, and stiff, mildly venomous leading spines in the dorsal, pectoral and adipose fins.
Its defining feature is the pattern that gives it its name. The ground colour is pale — whitish to faintly golden — overlaid with numerous well-defined small dark spots arranged in longitudinal rows across the body, and the fins, particularly the dorsal, are spotted as well. This spotted livery is shared with several congeners of the upper Araguaia and rio das Mortes, where a whole cluster of corys carry rows of black spots on a white to nearly orange base, so identification often rests on locality and fine pattern detail. As is typical of the genus, mature females are larger and rounder-bodied than the males.
Habitat
Corydoras maculifer is native to the upper rio Araguaia basin in central Brazil, in the rio das Mortes drainage of Mato Grosso — a Cerrado (savanna) region of clearwater streams and rivers running over sand. These are warm, generally clear waters with sandy bottoms, leaf litter and submerged wood, where the fish forages over open sand flats and along shallow margins.
The streams of the Araguaia/das Mortes system are typically warm and circumneutral to slightly acidic; FishBase reports a temperature preference around 77–81 °F and a pH band of roughly 6.0 to 8.0 for the species, with soft to moderately hard water. Like all Corydoras it is a facultative air-breather, periodically dashing to the surface to gulp air taken up through a vascularised hindgut, which lets it cope with the warm, sometimes low-oxygen conditions of shallow seasonal waters.
Feeding
Corydoras maculifer is a benthic omnivore and detritivore. It works the bottom continuously, driving its snout and barbels into sand to sift out small invertebrates, insect larvae, worms, micro-crustaceans, fallen seeds and organic detritus, and venting cleaned sand through the gill openings. It is an opportunistic forager rather than a specialist. In the aquarium its relatives take sinking pellets and tablets, frozen and live bloodworm, daphnia and brine shrimp, and graze whatever settles to the substrate, though they should receive a proper feeding rather than be left to scavenge leftovers.
Mating
Reproduction in the wild has not been specifically documented for this species, but Corydoras share a highly uniform courtship that is expected to apply. They are egg-scattering shoalers with no pair bond. A ripe female cleans a spawning surface while the group becomes active; a male takes up the classic 'T-position' at right angles to her head, and the female appears to take milt into her mouth and pass it rapidly through her gut to fertilise the few eggs she clasps in a basket formed by her pelvic fins, pressing them onto the cleaned surface. The bout repeats a few eggs at a time across the spawning surfaces.
Breeding
No widely documented spawning protocol exists specifically for Corydoras maculifer, which is an uncommon aquarium fish; the following is the general genus pattern. Spawning is typically triggered by a large, cooler water change mimicking the onset of the rains, in a mature group skewed towards more males than females. The adhesive eggs are laid in small batches on plants, wood, stone or glass and receive no parental care — the adults will eat them, so a breeder removes either the eggs or the parents. Eggs hatch in roughly three to five days, and the fry take microworm, baby brine shrimp and powdered foods once the yolk sac is absorbed. Fish in trade are predominantly wild-collected Brazilian imports.
In the aquarium
An attractive but less commonly seen spotted cory, Corydoras maculifer asks for the standard, undemanding care of its genus. It is a shoaling species and should be kept in groups of six or more, never singly or in pairs; in numbers it forages confidently throughout the day. A tank with a footprint of around 23.5 in / 20 US gal or more suits a group, with bottom area mattering more than height.
Provide soft sand or very fine, smooth, rounded gravel — corys feed by sifting, and coarse or sharp substrate abrades and infects their barbels, leaving the blunted faces that mark poor husbandry — and keep the bottom clean. Warm, clear, well-filtered and well-oxygenated water (about 73–79 °F) with a gentle current and regular changes mirrors its Cerrado-stream home while staying within a forgiving range. It is peaceful and suits a community of tetras, pencilfish, rasboras, dwarf cichlids and other calm fish, never anything large enough to bully it. The usual cory cautions apply: the fin spines snag in nets, so a cup is safer when moving them, and a badly stressed cory can release a skin toxin that, in the small volume of a transport bag, can kill the whole group.
Conservation
Corydoras maculifer has not been assessed by the IUCN Red List and so carries no formal conservation status. It is restricted to the upper rio Araguaia and rio das Mortes system, a Cerrado region of Mato Grosso under significant pressure from agricultural expansion — soy and cattle frontiers — with the attendant deforestation, soil erosion, siltation and agrochemical run-off that degrade clearwater streams. Range-restricted sand-stream specialists are exactly the kind of fish such changes can affect. The species does appear to be reasonably widespread within the das Mortes drainage, but without a formal assessment its population trend is unknown, and a proper evaluation would be needed before anything firmer could be said.