Taxonomy & naming
Corydoras amandajanea was described by David Sands in 1995, in a Freshwater and Marine Aquarium article naming four new Corydoras from tributaries of the upper Rio Negro. The type locality is given as the Rio Miuã system of streams — possibly the Uarinabe stream — some 6–7 mi from its confluence with the upper Negro, in an area corresponding to the region around São Gabriel da Cachoeira, Amazonas State, Brazil. The species is named for Mrs Amanda Jane Sands, the author's wife, whom he thanked for her help during the work.
The genus Corydoras Lacépède, 1803 had grown to over 170 species and proved, on molecular grounds, not to be a single natural lineage. The 2024 phylogenomic revision by Dias, Tencatt and colleagues split it into several genera. This species falls within Lineage 8 — the 'intermediate long-snouts' with deeper bodies — and is placed in the resurrected genus Brochis, the high-bodied lineage best known from the old 'Brochis' (e.g. the emerald catfishes). The Catalog of Fishes accordingly gives its current status as 'Valid as Brochis amandajanea (Sands 1995)'. This is exactly why the genus had to be checked rather than guessed: a fish that looks like a long-snouted Corydoras belongs, phylogenetically, with Brochis. We keep 'Corydoras amandajanea' as the heading, since that is how the hobby still refers to it, while recording the current combination.
Morphology
This is a medium-sized cory reaching roughly 2.5 in standard length, with a deeper body and a longer, intermediate snout than the familiar short-snouted corys — features consistent with its placement in the deeper-bodied Brochis lineage. As in all Corydoradinae it is armoured with two rows of overlapping bony scutes down each flank, a hard helmet-like head and three pairs of barbels around the inferior mouth.
Detailed diagnostic characters are hard to come by: even Seriously Fish notes it has been unable to obtain the original type description, and very little has been written about the species since 1995. It is reported to be somewhat variable in pattern, with some individuals carrying relatively larger dark spots on the body than others. As in its relatives, the dorsal, pectoral and adipose fins each bear a stiff leading spine; the pectoral spines can pierce skin and sting, and the axillary glands at the spine bases are thought to be mildly toxic.
Habitat
Corydoras amandajanea is known from the upper Rio Negro basin in Amazonas State, Brazil — the type material coming from the Rio Miuã stream system near São Gabriel da Cachoeira. This is classic blackwater country: tea-coloured, acidic, nutrient-poor water draining ancient, sandy, forested terrain. Little has been published about its specific microhabitat, but the congener C. crypticus was described from the same locality, so the two presumably occur together.
Reported aquarium parameters are warm and soft — a temperature band of about 72–79 °F, a pH from acidic to neutral-alkaline (roughly 6.0–8.0) and soft to moderately hard water — though, as with many obscure corys, these are general estimates rather than figures measured at the type locality, where genuinely soft, acidic blackwater would be expected. Like all Corydoradinae it is a facultative air-breather, taking gulps of surface air and absorbing oxygen through its modified, vascularised intestine.
Feeding
No diet study exists for this species, but Corydoradinae are uniformly benthic omnivores and detritivores. It can be assumed to forage over the bottom, sifting sand and leaf litter with its barbels to find small invertebrates, insect larvae, worms, micro-crustaceans and detritus, expelling cleaned substrate through the gills. In the aquarium it would be expected to take sinking dried foods along with small live and frozen items such as bloodworm and Tubifex, and a varied diet would keep it in condition.
Mating
No spawning observations specific to C. amandajanea have been published. The Corydoradinae as a whole share a well-documented courtship: egg-laying shoalers with no pair bond, in which a receptive female cleans a surface, a male adopts the classic 'T-position' at right angles to her head, and a few sticky eggs at a time are clasped in a basket formed by her pelvic fins and pressed onto the cleaned site. Whether this species departs from that pattern is simply unknown.
Breeding
Breeding of C. amandajanea has not, as far as the literature records, been documented — it is rare in the trade and little has been written about it. By analogy with related corys it would be expected to be an adhesive-egg layer, spawning in the T-position and scattering modest batches of sticky eggs across firm surfaces with no parental care, the fry taking micro-foods after absorbing the yolk sac. We present this explicitly as inference from close relatives rather than as an observed breeding record for this species.
In the aquarium
This is a rare fish that few aquarists will encounter; it appears in the trade only occasionally and there is little husbandry experience to draw on. Should specimens be available, the requirements would be those of a medium-sized blackwater cory: keep it as a shoal of at least six (it is peaceful and gregarious and should never be kept singly), over soft sand that suits its sifting habit and protects its barbels from the erosion and infection that sharp gravel causes. Given its upper-Negro origin it would likely do best in soft, gently acidic, warm, well-filtered water with some cover and subdued light. It is a calm, peaceable community fish for similarly gentle tankmates. The usual cory cautions apply: move them in a cup rather than a net, since the fin spines tangle, and transport them carefully, as a stressed cory can release skin toxins that may harm a whole group in the confined volume of a bag.
Conservation
Corydoras amandajanea (as Brochis amandajanea) was assessed by the IUCN in 2020 as Data Deficient — meaning there is not enough information on its distribution, population or threats to judge its risk of extinction. This is honest reflection of how little is known: the species is documented chiefly from its original description, from a narrow slice of the upper Rio Negro, and has scarcely been studied since. A Data Deficient listing is not a clean bill of health; a fish known from such a restricted area could be vulnerable to localised habitat change, and resolving its status would require basic survey work on its range and abundance.