Overview
Corydoras are small, peaceful armoured catfish from South America, with over 160 species in the trade. They patrol the bottom of the tank on stubby barbels, snuffling through the substrate for scraps, and are among the most charming and sociable fish you can keep.
They are a true shoaling genus , happiest and most active in groups , and their bony plates and mild toxin make them well-defended despite their small size.
| Care level | Beginner |
| Adult size | 1-3 in (2.5-7.5 cm) |
| Lifespan | 5-10 years |
| Temperament | Peaceful |
| Min. tank | 20 gal (76 L) |
| Temperature | 72-79°F (22-26°C) |
| pH | 6.5-7.5 |
| Hardness | 3-12 dGH |
| Diet | Omnivore (bottom feeder) |
| Schooling | Yes , keep 6 or more |
Water & tank conditions
Most common corys like 72-79°F, near-neutral pH and clean, well-oxygenated water. A few species (like sterbai) tolerate warmer tanks; match the species to your community.
Aquascape & setup
Give them a SOFT sand or smooth-gravel substrate , sharp gravel wears down and infects their barbels. Add shady spots (wood, plants, caves) and keep the bottom clean; they forage but are not a substitute for gravel vacuuming.
Diet & feeding
Omnivorous bottom feeders. Sinking pellets or wafers, bottom-feeder tablets and frozen bloodworms/tubifex should reach the substrate. They will not survive on other fish's leftovers alone , feed them directly.
Tankmates & schooling
Keep six or more of the same species; they shoal, forage and even breed better in numbers. Superb, peaceful community members alongside tetras, rasboras, guppies, dwarf cichlids and shrimp.
Breeding
Many species spawn readily: a cool water change can trigger a group, and the female carries fertilised eggs in a pelvic 'pouch' before sticking them to the glass and plants. The eggs and fry are easy to raise with clean water and fine foods.
Fun facts
- Corydoras breathe air by gulping at the surface and absorbing oxygen through their gut.
- They have bony armour plates instead of scales, which is where the family name (Callichthyidae, 'armoured catfish') comes from.
- They forage with taste-bud-covered barbels , soft sand keeps those barbels healthy.
- A simulated 'rain' (a cool water change) often triggers group spawning.
- With good care many corydoras live well over five years.
Frequently asked questions
How many corydoras should I keep?
At least six of the same species. Corydoras are shoaling catfish and are far more active, confident and healthy in a group than alone or in pairs.
Do corydoras need sand substrate?
Soft sand or very smooth, rounded gravel is strongly recommended. Sharp gravel abrades and infects their delicate barbels, which they use to find food.
Do corydoras clean the tank?
They help by eating leftover food and detritus from the bottom, but they are not a clean-up substitute , you still need to feed them directly and vacuum the substrate.
Are corydoras good community fish?
Excellent. They are peaceful, occupy the bottom level, and get along with almost all small, calm community species.
What do corydoras eat?
They are omnivorous bottom feeders. Offer sinking pellets or wafers and frozen foods such as bloodworms that reach the substrate where they forage.
