Corydoras are highly social creatures that thrive in the company of their own kind. In the wild, they move in massive shoals, and this instinct remains strong in the home aquarium. Keeping a single Cory or even a pair can lead to a stressed, shy fish that spends most of its time hiding.
To see their true personality, aim for a group of at least six individuals of the same species. When kept in a proper school, you will see them 'blink' at you, wiggle through the plants together, and confidently forage across the bottom of the tank.
The most critical physical requirement for Corydoras catfish care is the substrate. These fish have delicate barbels—the whisker-like sensory organs near their mouths—that they use to sniff out food buried in the ground. Sharp-edged gravel or coarse rocks can tear these barbels, leading to painful infections.
Fine, soft sand is the gold standard for Cories. It allows them to engage in their natural behavior of sifting through the grains without risk of injury. If you must use gravel, ensure it is extremely smooth and rounded to protect their sensitive faces.
While many Cory species are hardy, they are sensitive to poor water conditions, especially high nitrate levels. Since they spend all their time on the bottom where waste tends to accumulate, regular substrate vacuuming and weekly water changes are essential for their long-term health.
Most common species prefer a stable temperature between 72°F and 78°F and a neutral pH. Because they are intestinal air-breathers, you might occasionally see them dart to the surface for a quick gulp of air. This is normal behavior, but if it happens constantly, it may be a sign of low oxygen levels.
A common misconception is that Cories are 'scavengers' that can survive solely on the leftovers from other fish. While they do help clean up stray flakes, they require a dedicated diet to stay healthy. High-quality sinking pellets or wafers designed for bottom-dwellers should be the staple of their diet.
For variety, offer them frozen or live treats like bloodworms or brine shrimp once or twice a week. Ensure that the food actually reaches the bottom; if you have fast-swimming mid-water fish, you may need to feed your Cories after the aquarium lights have been turned off for the night.
Cories appreciate a well-decorated tank with plenty of cover. Broad-leafed plants like Anubias provide excellent shade, while driftwood and caves offer secure places for them to rest during the day. They are peaceful community fish that get along with almost any non-aggressive tank mate.
Avoid keeping them with large, predatory fish that might see them as a snack. Also, keep in mind that Cories have sharp defensive spines in their fins, so use a fine-mesh net or a container when moving them to prevent them from getting tangled or causing injury.
It is best to keep a minimum of 6 Corydoras of the same species. They are schooling fish and feel much safer and more active when they have a large group to interact with.
No, Corydoras are not algae eaters. They are omnivores that primarily eat small crustaceans, worms, and insects in the wild. They need meaty sinking pellets rather than algae-based food.
While you can keep them on very smooth, rounded gravel, sand is highly recommended. Sand allows for natural sifting behavior and is the safest option for preventing damage to their sensitive barbels.