Corydoras are remarkably consistent in their requirements. All are schooling fish, so should be kept in groups of at least five specimens, and the more the merrier! While different species will coexist kept together in the same aquarium, they won’t necessarily school together. It is therefore important to get at least five of each species, even if you plan on keeping two or more species in the same aquarium. Exceptionally, males are intolerant of one another, as is the case with Corydoras narcissus. Otherwise, both sexes tend to get along well with each other.
Feeding is very easy because these fish are opportunistic omnivores. In the wild they largely consume organic detritus, sifting out food particles from sand and silt. Algae, plant debris, tiny invertebrates and carrion are all important components of their diet. In captivity this aspect of their care is easily met by offering a variety of dried and frozen foods. Good quality catfish pellets and algae wafers will make an excellent staple, but these can be augmented with things like frozen bloodworms and mosquito larvae.
Corydoras are obligate air-breathers, and need to be able to swim up to the surface to gulp air periodically. In the wild they often inhabit creeks and streams less than 30 cm deep, and in very much deeper tanks they can easily drown. For tanks more than 45 cm, Corydoras are best replaced with river rather than stream-dwelling members of the family, such as Brochis spp.