Taxonomy & naming
Corydoras simulatus was described by Stanley Weitzman and Han Nijssen in 1970, in their account of new callichthyid catfishes from Ecuador, Colombia and Brazil (Beaufortia). The type locality is the Río Ocoá near Puerto López, in the Río Meta system of Meta department, Colombia. The epithet simulatus — 'imitated, counterfeit' — refers to its close resemblance to other long-snout corys, a likeness reflected in its hobby name 'masquerade cory.' It belongs to the family Callichthyidae and subfamily Corydoradinae, in the long-snouted morphological group.
The species has always been placed in Corydoras Lacépède, 1803. That genus proved not to be a single natural lineage, and the 2024 revision by Dias, Tencatt and colleagues (Zoological Journal of the Linnean Society) split it into several genera. C. simulatus falls in Lineage 1, the group retaining the name Corydoras in the strict sense (anchored on the type species C. geoffroy), so its combination is unchanged. It is most readily confused with C. septentrionalis of Venezuela, from which it differs in lacking the third (rictal) pair of upper barbels; the original description was brief, which has long limited fine-scale diagnosis.
Morphology
This is a long-snout cory with a distinctively concave, 'saddle-shaped' snout profile — the feature behind the 'saddle-snouted' name. It reaches roughly 2.5–3 in standard length, females growing about 0.5 in larger than males. The body carries the usual two rows of overlapping bony scutes; the barbels number the customary pairs, but the small rictal barbels at the mouth corners are reduced or absent, one of the characters separating it from the otherwise similar C. septentrionalis.
In colour it is a pale to greyish fish marked with dark blotching and a broken pattern that varies markedly with collection locality — the very variability that prompted the name simulatus, since different forms have at times been mistaken for other long-snout species. The dorsal, pectoral and adipose fins each bear a stiff defensive spine. Females in condition are visibly rounder and broader than the slimmer males, most obvious from above.
Habitat
Corydoras simulatus is endemic to the upper Río Meta watershed, a major Orinoco-system drainage of the Colombian Llanos, with the type material from the Río Ocoá near Puerto López. It is a fish of warm, flowing rivers and their margins over sand and fine sediment, with wood and leaf litter for cover.
Reported parameters sit in the standard cory range — temperatures around 68–77 °F, a pH from acidic to near-neutral (about 6.0–7.0) and soft to moderately hard water. The bottom is sand, into which it buries its long snout to forage. Like all corys it is a facultative air-breather, rising to gulp air absorbed across a vascularised hindgut, an adaptation for the warm, seasonally low-oxygen waters of the Llanos.
Feeding
C. simulatus is a benthic, foraging omnivore. Its long, concave snout is a digging and probing tool: it works it into the sand and uses the barbels to taste out insect larvae, small crustaceans, worms and the organic detritus of the bottom, expelling cleaned sand through the gills. In the aquarium it accepts sinking dried foods — pellets, tablets and granules — alongside small live and frozen items such as bloodworm and Tubifex. A varied diet keeps it in condition; it should not be left to subsist on tankmates' leftovers.
Mating
No spawning account specific to C. simulatus has been published, but the corys' courtship is uniform and well-documented. They are egg-laying shoalers with no pair bond. A ready female cleans a spawning site and the group becomes active; a male takes the characteristic 'T-position' at right angles to her head, and she appears to take milt into her mouth, fertilising the few eggs she clasps in a basket of her pelvic fins. She presses each small batch onto the cleaned surface, and the sequence repeats until the sticky eggs are distributed across plants, wood and glass.
Breeding
C. simulatus is not commonly bred in the aquarium and no clutch data specific to it are recorded, so its reproduction is expected to follow the genus pattern. The usual trigger is to condition the group well and then perform a cool, generous water change — dropping the temperature several degrees and raising oxygenation to imitate the rainy season. The adhesive eggs are laid in small batches and receive no parental care; adults will eat them, so breeders remove the eggs or the parents. Eggs hatch in roughly three to five days, and the fry take microworm and baby brine shrimp once the yolk sac is absorbed.
In the aquarium
A handsome but uncommon long-snout cory for the keeper who can source it. As a shoaling species it should be kept in a group of six or more; alone or in pairs it is stressed and inactive. Floor area matters more than height, and soft sand is essentially mandatory — long-snout corys feed by burying the snout, and sharp or coarse gravel abrades and infects the barbels, eroding the face and signalling poor husbandry. Keep the bottom clean, the water warm (about 68–77 °F — it does not want hot water), well-filtered, well-oxygenated and gently flowing, with regular water changes. It is peaceful and community-safe with tetras, rasboras, pencilfish and calm dwarf cichlids. Handle with a container rather than a net, because the fin spines snag, and transport with care, since a badly stressed cory can release skin toxins lethal to the group in the small volume of a bag.
Conservation
Corydoras simulatus is assessed by the IUCN as Vulnerable (assessed 2020). As a species endemic to the upper Río Meta, it has a restricted range, which raises its exposure to localised habitat pressures — agricultural expansion across the Llanos, deforestation, sedimentation and pollution of the rivers it depends on, alongside collection for the ornamental trade. The narrow distribution is the key factor in its elevated risk relative to the many widespread, Least-Concern corys, and makes the integrity of the upper Meta drainage central to its future.