Corydoras Catfish Care Guide
This page is educational reference material for preparing questions. A licensed veterinarian examines the animal, makes the diagnosis, and sets the treatment.
Complete care guide for Corydoras catfish covering species, tank setup, school size, feeding, breeding, and why they are ideal community fish.
Housing and Enclosure
Corydoras need a minimum 20-gallon aquarium with a soft, sandy substrate — gravel can damage their sensitive barbels. Maintain temperatures of 72-78°F and provide gentle filtration. They are social and must be kept in groups of at least 6 of the same species. Include caves, driftwood, and plants for shelter.
Diet and Nutrition
Feed sinking pellets or wafers designed for bottom feeders as the staple diet. Supplement with frozen bloodworms, brine shrimp, and blanched vegetables. Corydoras are not effective algae eaters — they need dedicated feeding, not just leftovers. Feed in the evening when they are most active.
Health and Veterinary Care
Common corydoras health issues include barbel erosion (from rough substrate or poor water quality), ich, and bacterial infections. They are sensitive to salt and many medications — use half doses of most treatments. Maintain pristine water quality with regular changes and a sandy substrate.
Common Health Issues
- Ammonia and nitrite poisoning: The most common aquarium problem. It follows an uncycled tank, overfeeding, a dead fish left in the tank, or a filter that stopped. Both should read 0 ppm.
- Temperature stress: Fish cannot regulate their own body temperature, so every body process follows the water. Use a thermometer, and a thermostat heater for tropical species.
- Ich and other parasites: Usually brought in on new fish or plants. Quarantine new arrivals in a separate tank before they join the display.
- Bacterial infections such as fin rot: Usually follow poor water quality or an injury.
- Medication harm: Copper treatments are toxic to shrimp, snails, and plants and can set back the filter bacteria, so ammonia and nitrite need watching for weeks afterward.
Source: Merck Veterinary Manual: Management of Aquarium Fish.
Stocking and Stress Reduction
- Float a new fish's bag to match temperature, then mix in tank water slowly before release.
- Add a few fish at a time so the filter bacteria can catch up with the extra waste.
- Check adult size, temperament, and water needs before buying a tank mate.
- Keep hands out of the tank when you can, and wash them before and after maintenance.
- Use a net only when you must; chasing fish around the tank is a stressor in itself.
Are corydoras good for beginner fish keepers?
Yes, they are hardy and peaceful, but they need a group of at least 6 of the same species, a tank of 20 gallons or more, and soft sand that will not wear down their barbels.
Can corydoras live on leftover food?
No. They are not cleanup crew. Feed sinking pellets or wafers as their staple, ideally in the evening when they are most active, and supplement with frozen foods.
While the upfront investment in a properly equipped aquarium (minimum 20 gallons for a school) represents a significant portion of the total cost, ongoing expenses for water treatment chemicals, filter media, electricity for heating and lighting, and food constitute the majority of long-term spending.