Pygmy corydoras (Corydoras pygmaeus)

A lot of new catfish species of Corydoras genus has appeared recently. Pygmy corydoras (lat. Corydoras pygmaeus) is one of them. It is an amazing, small fish, that got its name due to its tiny size. This species are not as brightly colored as other fishes, but its size is its sufficient advantage. It allows keeping pygmy corydoras even in nano tanks.

Habitat in the wild

Pygmy corydoras habitat is in South America, it is endemic species of Madeira river that flows in Brazil.

This is flooded forests area. The river water is very muddy, the flow is very slow and almost unnoticeable. The catfish often swim in large schools hiding among riverside vegetation or roots of trees.


Size is up to 3.2 centimeters (1.3 in), but as a rule they are not larger than 1 inch long (2-2,5 cm). The lifespan is up to 3 years long. The color of its body is olive drab with silvery tint.

The back is a bit darker than the abdomen. There is a black horizontal stripe along the body sides. It ends near the tail fin and becomes wider and with oval shaped ending. There is another thin black stripe below this one, that goes from anal fin to abdominal fin.

There is a pair of barbels on the fish maxilla and mandible. All the fins of this catfish are transparent.

Difficulties in keeping

The fish is not very demanding, peaceful and it doesn’t require roomy tanks. It can be recommended to both professionals and beginners as well as it can be kept in community tanks.

Keeping in a tank

Scientific NameCorydoras pygmaeus
Common NamePygmy corydoras, pygmy cory, dwarf corydoras, dwarf catfish, pygmy fish, pygmy catfish, dwarf cory
Tank size10 gallons and more
DietOmnivorous bottom feeders
Temperature72°F- 78°F (22 to 26 °C)
pH6.0 – 8.0
Sizeup to 3.2 centimeters (1.3 in), usual 1 inch long (2-2,5 cm)

To keep a small school of pygmy corydoras a tank volume starting from 10 US Gallons (40 liters) is enough. However, the larger the school is, the larger tank it requires.

In the wild the fish lives in water with the following parameters: 6.0 – 8.0 pH, water hardness 2 – 25 dGH and temperature 72°F- 78°F (22 – 26°C). You should try to maintain the same parameters in the tank.

As for the tank bottom substrate both small pebbles and large grained sand will do (the sand should be free-running and crumbly). Substrate with sharp edges may damage the catfish barbels, which makes it difficult for the fish to find food. You can also put some smooth stones on the bottom and the fish will eagerly rest on them.

Tank decorations such as snags, flower pots, coconut shells etc. will not only make the tank more appealing, but also become shelters for the fish. Tank plants will help in this respect, too and make the tank greener at the same time.

Pygmy corydoras like dim light. It’s desirable to put plants along the tank perimeter to leave free space for the fish to swim. Tank plants should have horizontal, wide leaves that are perfect for the catfish to have rest on them.

Since pygmy corydoras have intestinal respiration (they can breathe with atmospheric air due to their modified vascularized intestinal tract, when for some reason there is not enough oxygen in water), it is necessary to provide them with easy access to the water surface to get some air.

That’s why a water filter is a must in such a tank. But it doesn’t have to be a canister one, since it may create excessive water flow for such small fish. Aeration isn’t necessary. Once a week you should perform water renew in amount of 1/3 from the whole volume.

Compatibility and tank mates

In the wild corydoras live in small schools, that’s why in a tank they feel secure and comfortable in a school if at least 5-6 fish and 5-10 will be even better.

Though most of their relatives are bottom-dwellers, corydoras like spending much of their time in a middle water layer.

They are very peaceful and good-tempered tank mates, but considering their small size they should live with peaceful fishes of the same size (guppy, platy, swordtail, neon tetra, kuhli loach, cherry barb) and freshwater shrimps (red cherry shrimp, bamboo shrimp, Amano shrimp).


Pygmy catfish eagerly eat any kind of food: plant food, dry pellets, flakes or live and frozen food. They’ll gladly eat tubifex, daphnia, brine shrimp, cyclops. Keep in mind that the fish has tiny mouth and the food has to be fed in small pieces.

Pygmy corydoras mainly eats from tank bottom or from tank plant leaves or they even come to the water surface and get food there.

This fish is most active at night, that’s why one meal in the evening will not be enough for it. Though you can feed them during a day as well. Since the fish eats slowly it’s desirable that the food don’t stay on the tank bottom for a long time.

Gender differences: male vs female

It is easy to tell between the male and female due to their size: the male is thinner and smaller, the female is fatter and larger with rounded abdomen.


To stimulate breeding you should perform frequent water renews up to 50% of the total volume and raise water temperature by 2-3 °C, add intense aeration. Rise of atmospheric pressure also stimulates breeding.

If you have a thickly planted species tank with a school of not less that 12 corydoras and tank conditions are favorable for them, they will successfully breed themselves.

This catfish don’t eat their eggs, therefore you will not have to put the female into another tank. All you need is just to take care of the juveniles diet.

If school is smaller and there are other dwellers in the tank, then you’ll need a spawning tank for them.

A tank of 2.6 Gallons (10 liters) capacity will be enough. At that 1 female requires 2-3 males. it’d desirable to keep males and females separately for a week before spawning.

A “courtship” period precedes spawning: a male actively “dances” in front of the female showing its nice coloring, trying to make her interested.

When she finally turns her attention to him, the male touches her with his barbels and then they come into classical “T-position”, when the male keeps female’s barbels between its pectoral fins and its body.

The female takes its milt into her mouth and spawns eggs into her abdominal fins at the same time (about 2-5 eggs). The the female swims around the tank to find a proper place to put eggs. This may be a tank wall or tank plant leaves.

She cleans the spot she liked and greases it with milt and sticks eggs there. This way the female lays from 30 to 50 eggs.

After the spawning finishes, the fishes are put away and water temperature should be risen by 2-3 °C. To prevent fungal infection you may add some methylene blue into the water.

In 3-4 days the juveniles appear and for 3 days they feed on their yolk bag. Then you can feed the juveniles with dry food for juveniles or infusorian and later it can be brine shrimp nauplii and nematode.

Juveniles become reproductive at the age of 8 month. As a rule males become reproductive a bit earlier, then females.

About author: Sergey Schulz

Sergey is a founder and author of He’s been fond of aquarium husbandry since his early childhood. His favorite aquariums are biotopes (Amazon River), with Echinodorus and freshwater angelfish. However, through the years he’s had experience of keeping almost all types of freshwater fish and shrimps.