Corydoras are identified by their twin rows of armour plates along the flanks and by having fewer than 10 dorsal fin rays. They are most commonly confused with the other genera in the sub-family, namely Brochis, Scleromystax and Aspidoras.
There is some concern that Corydoras costai may not be a valid species, but may have been identified and characterized using a collection of slightly atypical individuals of Corydoras garbei (for holotype) and C. garbei mixed with Corydoras difluviatilis (for paratypes) to define C. costai. Eventually, C. costai may be reassigned as a synonym of C. garbei, but for now it is considered a valid species.
Shade provided by overhanging rock work, arching bogwood, tall or floating plants are all that is required. Ideally substrate should be sand, but rounded gravel is an imperfect alternative. Avoid keeping over rough edged (chipped) gravel, this will increase this risk of damage the fishes barbels when it tries to dig.
All Corydoras should be kept in groups of at least 6 of the same species. Otherwise compatible with most other types of fish that are reasonably peaceful, as long as they don't see a Corydoras as a snack.