Corydoras Catfish: Complete Species Care Guide

Medical Disclaimer: This article is for informational purposes only. Consult a veterinarian for diagnosis and treatment of fish health issues.

What Is a Corydoras Catfish?

Corydoras catfish (family Callichthyidae) are small, armored bottom-dwelling fish native to slow-moving rivers, streams, and floodplain ponds across South America. Their name comes from Greek: “kory” (helmet) and “doras” (skin), referring to the bony plates covering their bodies like armor. Over 170 described species exist, with bronze, albino, panda, and pygmy corydoras being the most popular in the aquarium hobby.

Corydoras are peaceful, social shoaling fish. In the wild, they form groups of dozens and spend most of their time sifting through sand for food. In the aquarium, they display the same behavior — constantly foraging, occasionally darting to the surface for a gulp of air, and resting together in groups. They are among the most beginner-friendly freshwater fish available and work well in community tanks with peaceful species of similar size. Their armored bodies and peaceful nature make them safe to add to almost any non-aggressive setup.

Corydoras Tank Requirements

Minimum Tank Size

A group of 6 corydoras needs a minimum 10-gallon tank. For community setups with other species, a 20-gallon long tank is recommended. Corydoras are bottom dwellers, so horizontal floor space matters more than water depth — a 20-gallon long tank provides more swimming area than a 20-gallon tall.

For more on tank size planning, see the care guides.

Water Parameters

Corydoras are among the first fish to show stress from ammonia spikes — they become lethargic and breathe rapidly at concentrations that other fish tolerate. Use a digital thermometer for accurate temperature monitoring and test strips to track water parameters weekly. An adjustable 50W heater maintains the 72-79°F range reliably.

Data source: FishBase.org (Corydoras aeneus), SeriouslyFish.com.

Substrate

Fine sand is non-negotiable for corydoras. Their barbels — the whisker-like appendages around the mouth — are sensitive sensory organs used to locate food in the substrate. Gravel and crushed coral have sharp edges that erode barbels over time, leading to infection and difficulty feeding. Pool filter sand or play sand are affordable alternatives to aquarium-specific sand.

Aqua Natural Sugar White Sand is a fine-grain bio-substrate that protects barbels and supports beneficial bacteria.

Filtration

Corydoras live in slow-moving waters in the wild and do not tolerate strong currents. A sponge filter provides gentle biological filtration ideal for species-only setups. In community tanks, a HOB or canister filter with a pre-filter sponge reduces flow at the intake and prevents corydoras from being drawn in.

For more on filtration, see the equipment section.

Hiding Spots and Decor

Add smooth rocks, driftwood, or decorative caves for hiding. Corydoras rest in sheltered spots during the day and become more active at dawn and dusk. Dim lighting or floating plants (water sprite, frogbit) simulate their shaded natural habitat and reduce stress.

Corydoras Diet and Feeding

What to Feed

Corydoras are omnivorous bottom feeders. Their primary diet should be sinking pellets or wafers formulated for bottom feeders. Supplement 2-3 times per week with frozen or freeze-dried bloodworms, brine shrimp, or daphnia.

Fluval Bug Bites Bottom Feeder Granules are protein-rich sinking granules designed for bottom feeders. Aqueon Shrimp Pellets are an affordable sinking alternative. For protein supplements, Hikari Freeze-Dried Bloodworms can be offered 2-3 times per week.

Avoid floating flakes — corydoras don’t often swim to the surface to eat and will go hungry while other fish consume the food.

Feeding Tips

• Feed once daily, dropping sinking food near their hiding spots
• Feed after lights-out or when mid-dwelling fish are distracted
• Remove uneaten food after 3-4 minutes to prevent water quality issues
• Overfeeding is the most common cause of health problems in corydoras tanks
• A corydoras group of 6 will consume 2-3 sinking pellets per feeding
• Soak freeze-dried foods for 3-5 minutes before offering to prevent digestive blockage

For general feeding guidance, see the feeding section.

Corydoras Tank Mates

Corydoras are peaceful and get along with most small, non-aggressive community fish. Since they occupy the bottom of the tank, they pair well with mid-water and surface-dwelling species that use different levels of the water column.

Ideal Tank Mates

• Neon tetras, ember tetras, harlequin rasboras: Peaceful mid-dwellers with similar water parameter needs
• Small livebearers (guppies, endlers, platies): Compatible, but avoid fancy guppy males with long trailing fins near corydoras
• Other corydoras species: Different species can school together, though same-species groups are more active
• Snails and shrimp: Nerite snails and amano shrimp share the bottom without conflict

Fish to Avoid

• Aggressive cichlids (Oscars, Jack Dempseys, African cichlids): Will eat or harass corydoras
• Fin-nippers (tiger barbs, serpae tetras): Attack corydoras barbels and fins
• Large predatory fish: Corydoras are small enough to be eaten

Use the stocking calculator to plan a balanced community. If fish show signs of stress, use the fish disease diagnosis guide.

Common Corydoras Health Issues

Barbel Erosion

Caused by sharp or coarse substrate (gravel, crushed coral). Affected barbels look shortened, frayed, or red and inflamed. Switch to fine sand immediately. With clean water, barbels regrow over 4-8 weeks. Add Seachem Prime to support water quality during recovery.

Ich (White Spot Disease)

Small white dots on body and fins. Corydoras are scaleless — use half-dose of ich medication to avoid chemical burns. Raise temperature to 82°F gradually (0.5°F per hour). See the ich treatment guide for detailed instructions.

Red Blotch Disease

Red sores on the belly indicate a bacterial infection, usually from poor water quality. Improve water conditions immediately with large water changes. Treat with antibacterial medication if the sores do not heal within a week.

Stress from Small Groups

A solitary or small group (fewer than 6) of corydoras will become withdrawn, stop eating, and hide constantly. The solution is simple: add more corydoras. For health concerns, consult the health section.

Popular Corydoras Species

Bronze Corydoras (Corydoras aeneus)

The most common and hardiest species — ideal for first-time corydoras keepers. Grows to 2.5 inches with a bronze-green metallic sheen. Extremely adaptable to various water conditions, tolerating 72-80°F and a wide pH range. Usually priced at $2-5 per fish.

Albino Corydoras (Corydoras aeneus var.)

The same species as bronze corydoras with a recessive albino gene. Identical care requirements. Pinkish-white body with red eyes. Same hardiness and adaptability as the bronze variety.

Panda Corydoras (Corydoras panda)

Distinctive black patches on a white body, named for their resemblance to giant pandas. More sensitive to temperature fluctuations — strictly 72-77°F. Grows to 2 inches. Priced at $5-8 per fish.

Pygmy Corydoras (Corydoras pygmaeus)

The smallest corydoras species at only 1 inch fully grown. Unlike most corydoras, pygmy corydoras school in the mid-water column and swim in tight groups rather than staying on the bottom. This unique behavior makes them a visually distinct addition to planted tanks. Ideal for nano tanks with a minimum of 5 gallons. More sensitive to water quality than larger species — maintain strict water change schedules.

Peppered Corydoras (Corydoras paleatus)

Speckled salt-and-pepper pattern. Among the few corydoras that tolerate cooler water (68-77°F), making them suitable for unheated tanks. One of the first corydoras introduced to the aquarium hobby in the late 1800s.

Sterbai Corydoras (Corydoras sterbai)

Distinctive bright orange-yellow pectoral fin rays. Prefers slightly warmer water (77-82°F) compared to most corydoras. Considered one of the most attractive species. Priced at $8-12 per fish.

Corydoras Behavior

Corydoras are most active during dawn and dusk, reflecting their natural crepuscular habits in the wild. They spend the day resting in groups near decorations and foraging through the sand. Periodically, they dart to the surface to gulp air — this is normal behavior using their modified intestine (intestinal labyrinth) to absorb atmospheric oxygen, not a sign of distress.

In a properly maintained group of 6 or more, corydoras display interesting social behaviors: coordinated group movements, mutual “wiggling” during courtship, and occasional group rests where they line up along the same surface.

For more on fish behavior, see the species index.