Small but Spectacular: Pygmy Corydoras Care Tips

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

The Pygmy Corydoras belongs to the Callichthyidae family, also known as armored catfish or cory catfish family. These small and peaceful fish are part of the Corydoras genus, which includes various species of catfish commonly kept in aquariums. Pygmy Corydoras (Corydoras pygmaeus) are well-liked among aquarists for their small size, interesting behavior, and ability to help keep the aquarium substrate clean by scavenging for leftover food.

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.

They are found in slow-moving waters, such as small creeks, tributaries, and flooded forest areas. Their natural habitat is characterized by soft, acidic water with a lot of vegetation, submerged branches, and leaf litter. The water temperature in their native range usually ranges from around 72°F to 78°F (22°C to 26°C), and the pH level is slightly acidic, typically between 6.0 to 7.0.



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.


Pygmy corydoras 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). Their small size makes them a popular choice for aquarists, especially in smaller aquarium setups or community tanks with other peaceful fish.

Despite their tiny size, these fish have a fascinating and social behavior, making them delightful additions to a well-maintained aquarium. Their small stature also means they require less space compared to larger fish, but it’s still important to provide them with an appropriate environment that replicates their natural habitat to keep them healthy and happy.


The lifespan of dwarf corydoras typically ranges from 3 to 5 years in a well-maintained aquarium environment. However, it’s essential to note that the lifespan of any fish can be influenced by various factors, including water quality, diet, tank size, genetics, and overall care.

Providing suitable living conditions, a balanced diet, and a stress-free environment can contribute to maximizing the lifespan of dwarf corydoras and promoting their overall health and well-being. Regular water changes, proper filtration, and keeping them in a compatible community with non-aggressive tank mates can also have a positive impact on their longevity.

Scientific NameCorydoras pygmaeus
Common NamePygmy Corydoras, pygmy cory, dwarf corydoras
FamilyCallichthyidae (Armored catfish or Cory catfish)
OriginAmazon River basin, South America
Adult SizeAround 1 inch (2.5 cm)
Lifespan3 to 5 years
Tank SizeAt least 10 gallons (38 liters)
Water Temperature72°F to 78°F (22°C to 26°C)
pH Range6.0 to 7.0
Water Hardness2 to 8 dGH
BehaviorPeaceful, social, and active
DietOmnivorous – They eat small invertebrates and algae
Tank LevelBottom-dweller, occasionally mid-level swimmers
CompatibilityPeaceful, suitable for community aquariums
Group SizePreferably kept in groups of 6 or more
Breeding DifficultyModerate

Difficulties in keeping

The pygmy corydoras 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

Tank size

To keep a small school of pygmy corydoras a tank volume starting from 10 gallons (approximately 38 liters) is enough. However, the larger the school is, the larger tank it requires. These small catfish are social and prefer to be kept in groups, so having a larger tank allows you to keep a small school of them, which is more natural and beneficial for their well-being.

A larger tank provides more swimming space, allows for better water quality maintenance, and reduces territorial conflicts among fish. With a 10-gallon tank, you can keep a small group of 6 to 8 Pygmy Corydoras comfortably. If you plan to keep a larger group or have other fish in the aquarium, consider getting a tank that’s at least 20 gallons (approximately 76 liters) or more.

Remember that the tank size is just one aspect of creating a suitable environment for these fish. It’s also essential to provide plenty of hiding spots, suitable substrate, and maintain proper water parameters to ensure the health and happiness of your pygmy corydoras.

Water parameters

In the wild the pygmy corydoras lives in water with the following parameters: 6.0 – 7.0 pH, water hardness 2 – 5 dGH and temperature 72-78 °F (22 – 26 °C).

Here are the recommended water parameters for pygmy corydoras:

  1. Temperature: 72°F to 78°F (22°C to 26°C)
    Pygmy Corydoras prefer slightly warmer water, so keeping the temperature within this range will ensure their comfort and well-being.
  2. pH Level: 6.0 to 7.0
    These catfish are adapted to soft and slightly acidic water conditions, so maintaining a pH level within this range is crucial for their health.
  3. Water Hardness: 2 to 8 dGH (degrees of general hardness)
    Pygmy Corydoras are typically found in waters with low to moderate hardness, so it’s best to keep the water hardness within this range.
  4. Ammonia, Nitrite, and Nitrate Levels:
    It’s essential to keep ammonia and nitrite levels at 0 ppm (parts per million) since these substances are toxic to fish. Nitrate levels should be kept as low as possible, ideally below 20 ppm, to prevent water quality issues.

Remember to use a reliable water test kit to monitor the water parameters regularly and make adjustments as needed. Stable and suitable water conditions will help ensure the health, longevity, and overall well-being of your corydoras in the aquarium.

Tank decor

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.

tank mates

In the wild pygmy 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.

In a well-populated group, these tiny catfish will feel more secure, display natural schooling behavior, and generally be less stressed. A larger group also provides a more interesting and dynamic display in the aquarium, as they interact with each other and move together in a coordinated manner.

They are very peaceful and good-tempered tank mates, but considering their small size they should live with peaceful fishes of the same size:


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 pygmy corydoras 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

Distinguishing between male and female Corydoras pygmaeus can be a bit challenging as they exhibit minimal sexual dimorphism, meaning the physical differences between males and females are not very pronounced. However, there are some subtle characteristics that can help differentiate them:

  1. Size: In some cases, females may be slightly larger and broader-bodied than males, but this difference is not always very noticeable.
  2. Body Shape: Females may have a slightly rounder and fuller belly, especially when they are carrying eggs.
  3. Coloration: Some aquarists report that females may appear slightly darker in color compared to males, but this can vary among individuals and is not a reliable method of sexing them.
  4. Vent Position: The most reliable method to determine the sex of pygmy corydoras is by looking at the vent, which is the opening located behind the pelvic fins. In mature females, the vent is typically more round and broader, while in males, it is more pointed and narrower.

Keep in mind that these differences are subtle, and it might be challenging to sex pygmy corydoras accurately unless you have experience or are observing a group of them, making it easier to compare individuals.

If you are interested in breeding pygmy corydoras, observing their behavior during spawning is a more definitive way to identify males and females. Females will lay eggs, and males will fertilize them as part of the breeding process. Otherwise, in a typical community aquarium setting, determining the sex of pygmy corydoras might not be essential, as they will exhibit similar behavior and care requirements regardless of their gender.


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 pygmy 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 pygmy corydoras 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 pygmy corydoras 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 pygmy corydoras 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.