🐟 AquaticCare difficulty: BeginnerLegal complexity: Low
Pygmy Cory
Corydoras pygmaeus · also called Pygmy Corydoras, Pygmy Catfish, Dwarf Cory, Pygmaeus Cory
A nano-sized armored catfish that, unlike most corydoras, shoals throughout the mid-water rather than just the bottom. Tiny, peaceful, and highly social, it is a charming choice for planted nano and community tanks with small, gentle tankmates.
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Quick facts
| Size | One of the smallest corydoras, reaching only about 2-3 cm (0.8-1.2 in), silver with a dark lateral stripe. |
| Lifespan | 3–5 years |
| Social needs | group |
| Native region | South America (Madeira River basin, Brazil) |
| Origin | New World |
| Climate | 🌴 Tropical |
| Water type | 💧 Freshwater |
| Family | Callichthyidae |
| Genus | Corydoras |
Part of the Catfish
Catfish are a diverse order of mostly bottom-dwelling fish, including peaceful shoaling corydoras, armored loricariids, and scavengers prized for keeping the lower levels of an aquarium active and clean.
Habitat & space requirements
From the minimum an animal needs to be kept humanely, up to the ideal setup. Bigger is almost always better — minimums are floors, not targets.
Life & growth stages
How this animal changes through its life — each stage often has its own care, diet and space needs.
Habitat & enclosure
Because they stay so small, a group thrives in a tank of at least 40-60 litres (10-15 US gal), but they need company: keep eight or more, as larger shoals school tightly in mid-water. Provide a soft sand substrate, dense planting, driftwood, and gentle flow, with fine-leaved plants giving the cover and security they favor.
They are tropical: keep water at 22-26 C (72-79 F), pH 6.0-7.5, soft to moderately hard, in stable, mature conditions. Being so small, they are sensitive to poor water quality and to being outcompeted, so gentle filtration and regular water changes are important.
Substrate
Use a soft, fine sand substrate to protect their delicate barbels and allow natural sifting. Add fine-leaved plants and driftwood, which they perch on and shelter among.
Equipment & setup
Provide gentle filtration, such as a sponge filter, that keeps water clean without strong current or risk of pulling in these tiny fish, plus a heater for stable warmth. Dense planting and subdued lighting suit their shy, schooling nature.
Diet
Micro-omnivores that need small foods: offer micro pellets, crushed flake, baby brine shrimp, daphnia, cyclops, and finely chopped frozen bloodworm. They forage along the bottom and pick food from plant leaves and mid-water.
Because their mouths are tiny, ensure foods are small enough and that enough reaches them past faster tankmates. Feed small amounts a couple of times a day, and avoid large or aggressive feeders that would intimidate them away from food.
Behavior & temperament
Peaceful, timid, and intensely social; they should be kept in groups of eight or more and feel insecure in smaller numbers. Uniquely for corydoras, they shoal in mid-water as well as on the bottom, drifting together and resting on plant leaves. Ideal tankmates are small, gentle fish such as nano tetras, rasboras, and dwarf shrimp.
Avoid any fish large enough to eat them, as these tiny catfish are vulnerable. In a large group they are confident and active, hovering and grazing together; kept alone or in pairs they hide and fail to thrive.
Health
Their small size makes them sensitive to water-quality swings, ich, and to salt and copper medications, which must be reduced. Barbel erosion from sharp or dirty substrate also affects them, so keep a soft, clean bottom.
They ship and acclimate poorly due to their size, so drip-acclimate carefully and add them to a mature, stable tank. Quarantine new fish, keep nitrates low with frequent small water changes, and ensure they are not outcompeted for food, which can lead to wasting.
Tips, DIY & hacks
Keep a large shoal, ideally ten or more, to bring out their tight mid-water schooling. Use a sponge filter to avoid trapping such small fish, drip-acclimate slowly, and pair only with peaceful nano tankmates that cannot eat them.
Sources
- Corydoras pygmaeus - Wikipedia (wiki)
- Pygmy Cory (Corydoras pygmaeus) - Seriously Fish (care guide)
- Wikipedia: Pygmy Cory (wiki)