Corydoras Catfish Care Guide
Corydoras are the perfect beginner fish, peaceful, hardy, entertaining to watch, and excellent community tank citizens. Keep them in schools on a soft sandy substrate and they'll thrive for over a decade.
Quick Facts
Tank Size Requirements
Myth: A single corydoras makes a fine tank cleaner
Corydoras are shoaling fish that become stressed and withdrawn when kept alone or in pairs. They need a group of at least 4-6 of the same species to display natural foraging and social behavior. They are also not a substitute for maintenance. They need to be fed their own food.
Minimum Requirements
- Minimum: 20 gallons for a school of 4-6
- Substrate: Fine sand is essential, gravel damages their sensitive barbels
- Filter: Gentle flow preferred (corydoras don't like strong currents)
- Hiding spots: Driftwood, caves, and plants help them feel secure
- Lid: Recommended, they occasionally jump when startled
Corydoras are armored with bony lateral plates and have spines on their pectoral fins, so handle them carefully when moving or netting. They are highly adaptable and do well in most peaceful community setups.
Ideal Water Parameters
Important: Salt Warning
Corydoras are unusually sensitive to aquarium salt compared to most freshwater fish. Never use salt treatments in a corydoras tank, even at doses safe for other species. If treating ich or other diseases, use salt-free medications and temperature only.
Diet & Feeding
Corydoras are omnivores and opportunistic bottom feeders. They do eat some tank debris, but they require dedicated feeding with sinking foods, they cannot live on leftovers alone.
Recommended Foods
- Staple: Sinking wafers or pellets formulated for bottom feeders
- Treats: Frozen bloodworms, brine shrimp, daphnia (2-3x per week)
- Vegetables: Blanched zucchini or cucumber occasionally
- Avoid: Floating foods they cannot easily reach at the surface
Feeding Schedule
- Timing: Feed in the evening when lights dim, corydoras are more active then
- Amount: What the group consumes within a few minutes
- Competition: Ensure food reaches the bottom before mid-water fish eat it all
Tank Mate Compatibility
Corydoras are one of the most universally compatible freshwater fish, peaceful, non-territorial, and they occupy the bottom layer leaving mid and top water for other species.
Common Diseases & Treatment
Barbel Erosion
Barbels (whiskers) are visibly shortened, eroded, or missing entirely
Sharp gravel substrate abrades sensitive barbels; worsened by bacterial infection
Switch to fine sand immediately, improve water quality, antibacterial medication
Red Blotch Disease
Red sores on body, lethargy, loss of appetite. Bacterial infection from stress.
Rx: Improve water quality + antibacterials
Ich (White Spot)
White spots on body and fins, scratching against objects. Common with new fish introductions.
Rx: Raise temp only. NO aquarium salt
Prevention is the best medicine
Sand substrate alone prevents the most common corydoras-specific problem. Combine with clean water and proper feeding, and corydoras are remarkably resilient.
Quick Tips
- Keep at least 4-6 of the same species, corydoras are miserable without a school
- Use fine sand substrate; gravel or sharp rocks erode their delicate barbels
- Never use aquarium salt in a corydoras tank, they are unusually salt-sensitive
- Seeing them dart to the surface for a gulp of air is normal, they can breathe air
- Feed sinking wafers at night when lights dim for best feeding response
- They have sharp pectoral spines, use a container (not a net) when moving them
- Cooler water (72-78°F) distinguishes them from most tropical fish, plan tankmates accordingly
Frequently Asked Questions
How many corydoras should I keep together?
A minimum of 4-6 of the same species. Corydoras are shoaling fish and become stressed and inactive when kept alone or in small numbers. More is always better, a large school of 10+ is a joy to watch.
Can corydoras live with bettas?
Yes, corydoras are one of the most recommended betta tank mates. They occupy different water levels, have armored bodies that protect them, and are not nippy. Make sure the tank is 20+ gallons and has hiding spots.
Do corydoras need to come up for air?
Yes, corydoras have a modified intestine that lets them breathe atmospheric air, which is completely normal. You will see them dart to the surface periodically. If they are doing it excessively, check oxygen levels.
What is the best substrate for corydoras?
Fine play sand or pool filter sand is ideal. It mimics their natural environment, lets them sift through it naturally, and is gentle on their sensitive barbels. Avoid gravel, particularly sharp-edged gravel.
Related Resources
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