Taxonomy & naming
This is an undescribed form: no scientific name, authority or type material stands behind it, and its identity and range are not documented in the sources the atlas uses. C123 is a hobby C-number. Imperial Tropicals lists it as Gastrodermus sp. (C123), the lineage that holds Corydoras elegans after the 2024 revision. Dan's Fish sells it as "C123 Yellow Cory 'Rio Nanay'" and places it in the Corydoras elegans complex.
Morphology
Imperial Tropicals describes the same body shape and tan or silver colour as the elegant cory, with brown or dark grey stripes and striations. What sets it apart, according to the seller, is yellow fins that develop when the fish is mature and settled, in both sexes, though the seller says males may be richer.
Habitat
Imperial Tropicals says it is known only from forest streams and tributaries of the Rio Nanay basin in Peru, which it describes as slow, shallow and sandy-bottomed with fallen organic debris. Dan's Fish labels its stock "Rio Nanay" and "harvested from nature".
Feeding
Corydoradines are bottom-feeding omnivores that sift sand with their barbels (genus-level); no diet is documented for this form.
Mating
Like other corydoradines, the genus spawns in the T-position, the female carrying eggs in her pelvic fins before sticking them to a surface. Spawning of this form is not documented.
Breeding
No captive-breeding record for this form is held by the atlas.
In the aquarium
Dan's Fish lists an adult size of around 1.5–2 in and notes that its young stock had not yet developed full colour. The fish is wild-caught; keep it in a group on sand.
Conservation
No IUCN assessment exists for this undescribed form. Its range and numbers are not documented, so its conservation status cannot be stated.