Corydoras Care Guide: How to Keep Happy, Healthy Cory Catfish

Corydoras catfish (or just 'corys') are some of the most beloved fish in the freshwater hobby — peaceful, social, endlessly active, and absolutely safe with even the smallest tankmates. They're also an affordable choice, earning a spot on our list of the best freshwater fish under $20. They scoot around the bottom in groups, dart up to the surface for a gulp of air, and pile on top of each other when they sleep. If you want a community tank with personality on the bottom, corys are the answer — and a top bottom-dweller pick in our best fish for a planted aquarium guide. This guide walks you through everything: choosing the right species, why sand matters, what to feed them, tankmates, breeding, and a tour of the corys we currently stock at Tropical Treasures Wyo.

Why Corydoras Are Great Community Fish

Corys check every box for a community tank: they're peaceful, hardy once acclimated, occupy the bottom layer (a niche most fish ignore), and come in dozens of patterns and sizes. They don't outgrow normal tanks, they don't eat other fish, and they don't fight with their own species. The catch? They have a few specific care needs — especially around schooling, substrate, and diet — that get overlooked all the time. Get those right and you'll have one of the most rewarding fish in the hobby.

Schooling Is Non-Negotiable

Corys are deeply social. Keep them in groups of at least six of the same species — eight or more is better. A single cory or pair will hide, stop eating, and slowly waste away. A proper school will be out front and center most of the day, foraging together.

Mixing species (a few panda + a few peppered, for example) doesn't count as a school. Same-species groups actually shoal, breed, and behave naturally. If you want variety, pick two species and keep six of each.

Cory Species We Stock

Browse the full Corydoras collection for current availability. Here's how species break down by tank size.

Nano Tanks (10–20 gallons)

A school of 8–10 pygmies in a planted 10-gallon is one of the most rewarding nano setups you can build.

Mid-Size Tanks (20–29 gallons)

Standard Community Tanks (29+ gallons)

Tank Setup for Corydoras

Substrate: Sand Is Critical

This is the single most important setup choice. Corys forage by digging their barbels (the 'whiskers' around their mouth) into the substrate to find food. Sharp gravel literally erodes those barbels away, leading to infections and a fish that can't feed properly. Use fine, smooth sand. Our favorites:

If you already have gravel and aren't ready to swap, at minimum make sure it's small, smooth, and rounded.

Plants, Wood, and Hiding Spots

Corys love structure. Add driftwood, smooth river stones, and live plants. Floating plants help dim the light (corys are happiest in slightly shaded tanks). See our plant care basics for low-tech plant ideas.

Water Parameters

  • Temperature: 72–78°F for most species; peppered corys prefer 70–75°F
  • pH: 6.5–7.5
  • Ammonia/nitrite: 0 ppm; nitrate under 20 ppm

Use a quality heater, test weekly with an API Master Test Kit, and dose Seachem Prime at every water change. Always cycle your tank first — see our cycling guide.

Filtration and Flow

Corys appreciate moderate flow — not a calm pond, not a torrent. They evolved in slow streams with currents from rainfall, so a gentle wave across the tank is ideal. Make sure intake guards are in place; pygmy corys can get sucked up by powerful filters.

Feeding Corydoras (They Are NOT a Cleanup Crew)

The biggest myth: 'corys will eat the leftovers.' They won't. Or rather, they won't get enough. Corys need their own dedicated food, dropped where they can find it.

Best Foods for Corys

How and When to Feed

Drop food right after lights-out so corys get to it before the mid-water fish swarm. Aim for an amount they finish in 5–10 minutes. Once weekly, fast them for a day to mimic natural feeding gaps. Overfed corys get bloated and lazy — underfed corys go skinny in the belly. Watch and adjust.

Best Tankmates

Corys play well with virtually all peaceful community fish:

Avoid: large or aggressive cichlids, large carnivorous plecos at night, and any fish big enough to swallow them. Bettas are usually fine, but watch fin-nipping behavior in either direction. Warmth-loving species like the Sterbai cory also make excellent bottom dwellers in a discus tank — see our guide to the best tank mates for discus.

Why Do Corys Dart to the Surface?

Corydoras are facultative air-breathers — they have a modified intestine that absorbs atmospheric oxygen. Occasional gulps are completely normal. If they're doing it constantly, though, your water has an oxygen problem or ammonia/nitrite is elevated. Test immediately, do a water change with Prime, and add an airstone.

Breeding Corydoras

Bronze and peppered corys are among the easiest egg-layers in the hobby. The trick:

  1. Get a school of 6+ with at least 2 males per female (females are larger and rounder)
  2. Condition with high-protein foods (frozen bloodworms, brine shrimp) for a week
  3. Do a large (50%) cool water change — drop the temperature 4–5°F. This mimics the rainy season that triggers spawning.
  4. Within a day or two, females lay sticky eggs on glass, plants, or filter intakes
  5. Move eggs to a separate fry tank (parents will eat them); add a drop of methylene blue to prevent fungus
  6. Fry hatch in 4–5 days; feed baby brine shrimp and powdered fry food

Common Problems & Health

  • Eroded barbels: sharp substrate or poor water quality. Switch to sand and improve maintenance.
  • Skinny belly / hollow sides: underfed or internal parasites. Increase food variety; quarantine new arrivals — see our quarantine guide.
  • Constant surface gulping: oxygen or water-quality emergency. Test, water change, add airstone.
  • White spots (ich): classic stress disease. Move to a hospital tank for treatment — corys are sensitive to many meds, so use cory-safe products at half dose.
  • Refusing to school: usually means too few of the same species. Add more.

FAQ

Can I keep different cory species together? They'll coexist, but each species needs its own school of 6+ to truly thrive. Don't mix 3 pandas with 3 peppered and call it a school of 6.

Do corys need a heater? Yes for most species. Peppered corys can handle room temperature in many homes, but a heater ensures stability.

How long do corydoras live? 5–10 years with good care; some bronzes hit 15.

Are corys shrimp-safe? Adult corys generally ignore cherry shrimp. Shrimplets may get eaten if they end up in front of a hungry cory, but it's rare.

Why is my cory lying on its side? Corys do sleep on their side or wedged into plants — that's normal. If they're lying flat and not eating, it's an emergency.

Visit Us in Cheyenne

We rotate cory species frequently. Stop into our Cheyenne, WY shop or browse our full Corydoras collection online to see what's in this week. Need help picking a school for your tank? Contact us — we'll help you build the perfect community.

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