In the wild, most Corydoras swim in schools of several dozen or more, and similar conditions should be duplicated in the home aquarium. The Corydoras aeneus should be kept in a group of six or more with other community tank fish, such as small characins, livebearers and rasboras. Kept as a single specimen, it is shy and easily frightened, while keeping it in groups will give it a sense of security and allow the aquarist the opportunity to observe their comical behaviors. Avoid large, aggressive fish, such as cichlids and large barbs, as tankmates.
This fish should be housed in a tank with a substrate of dark-colored fine gravel or coarse sand to protect its barbels. A shallow tank is preferred because the fish will occasionally come to the surface for a gulp of air. The tank should be heavily planted with bunch plants (live or artificial), such as Elodea and Cabomba, as well as root plants like swordplants and Vallisneria, which will also act as hiding places. Decorate with driftwood and smooth rocks, leaving plenty of room in the center for swimming.
The cory will accept a wide variety of live, frozen and freeze-dried meaty foods. Live foods, such as Tubifex worms, earthworms, bloodworms, glass worms and brine shrimp are especially preferred. Supplement its diet with vegetable-based flake and pelleted foods.
Although it is possible to differentiate between the sexes, to ensure spawning success it is best to purchase a group. Condition on small feedings of a high-protein diet that consists of small live foods, several times per day.
Spawning is preceded by a long courtship ritual consisting of chasing bouts interrupted by cleaning of potential spawning sites. Once courtship is finished, the cories lock together in the “T” position — the female with her head nudged into the side of the male near his vent, the male clasping her barbels to his sides with his pectoral spines. The eggs are fertilized, the pair unclasps and the female deposits the eggs. The Corydoras aeneus often uses the sides of the aquarium, the plastic filter box, the sponge media of an inside or sponge or individual plant leaves, on which to deposit clusters of eggs. Most other species of Corydoras deposit only two to four eggs per leaf, repeating the process for an hour or two until 100 or more eggs have been deposited.
The spawning bouts are repeated over and over until the female is depleted of eggs. Once spawning is completed, the eggs should be transferred to another tank where they will hatch in two to 10 days.