Pygmy corydoras are small catfish native to South America, mainly from the Amazonian habitat. In nature, they live in small streams, tributaries, ponds, and flooded forest areas, and it is common to find them in large numbers, sheltered between the roots of trees and marginal vegetation.
The scientific name uses the Latin word “pygmaeus” which means small or dwarf, and refers to its small size, being the species that reaches the shortest length in the genus Corydoras.
They are characterized by having a silver color with a continuous black band along the side, from the barbels to the base of the caudal fin, interrupted only at the height of the gills. These small, sociable fish are commonly called “corys” and are often a popular addition to personal aquariums, as they are peaceful and easy to care for.
If given the right habitat conditions and diet, they can thrive and live their short life in perfect conditions.
How big do Pygmy corydoras get?
They are one of the smallest Corydoras out there. The females are somewhat larger and thicker than the males, which is more noticeable when looking at them from above, with a size of around 2.54 cm and the males reach 1.90 cm. In any case, specimens of this species rarely exceed a maximum length of about 3 cm to 3.2 cm.
How many pygmy corydoras should be kept together?
These peaceful, shy and gregarious fish need to live in a group, the more numerous the better, as this will help them to be less cautious and they will move more around the aquarium.
It lives in groups in the wild so it’s best to buy at least 6, preferably 10 or more, and starting from 12 individuals, their behavior will be close to the one they have in nature.
Expert Tip: A very important social aspect among Corydoras that fosters group bonding is learning by sounds and mimicry. Corydoras make sounds that they have to adjust to the same frequency in order to understand each other.
This apprenticeship is long, and the group can take between 4 and 8 months to form a united shoal. Likewise, through this learning of sounds, the fry will learn to dig and feed properly, and they will learn the behavior of adults by mimicry.
To encourage this union in the shoal, it is advisable to buy the entire school of corys at once, but if this is not possible and different groups join, it must be taken into account that they will need time to function and act as a single group since at first, they will not understand each other and will not communicate correctly.
Habitat and Tank Conditions
As previously mentioned, their original habitat is the Amazon basin: they mainly inhabit the Madeira River and its tributaries in Brazil, the middle Amazon basin in the Mato Grosso region, the mouth of the Jiparana River in Paraguay, the Loreo River in Peru, and the Aguarico River in Ecuador.
In their natural habitat in the rivers of South America, it is normal to have abundant vegetation and stems, which is ideal for hiding.
Size, Environment, and Substrate
Due to their size, they can live in small aquariums, but it is important to have them in a tank that has more than 60 liters of capacity. Bushy plants with many stems at the base are important, which is why it is essential to have abundant vegetation in the middle to lower part and shady areas where they can hide and rest.
Corydoras are bottom feeders. They also like to swim and explore near the bottom of the aquarium. The substrate should preferably be sandy and fine, non-abrasive, with a minimum depth of 5 cm (2 inches), so they can dig in the sand in search of food, exactly as they do in the wild.
Another function of the sand is to contribute to oral hygiene since when digging the sand, they suck it up at full speed and throw it through their gills. This operation has an abrasive effect on certain parasites located in the gills.
Corydoras are resistant fish that know how to adapt but prefer certain conditions to be healthy. The pH level of the water should be slightly acidic to neutral, approximately 7.0 with normal levels being those between 6.4 to 7.4. The water temperature range should be between 21 and 25 C (70 and 78 F).
Expert Tip: Pygmy Corydoras tolerate nitrates poorly, which requires good filtration, a fairly mature aquarium with regular water changes. Low levels of nitrates and ammonia should be as follows: N02: 0 mg/l. and N03: < 20 mg/1.
Corydoras are omnivorous catfish, meaning that they consume both plant and animal material. In freedom, they feed on worms, crustaceans, and insects, and in captivity, they will accept almost any type of food that they find on the bottom, so they will eat the granules and flakes that sink to the bottom of the aquarium.
To give them a treat from time to time, frozen and live foods that sink can be placed, such as sifted brine shrimp or daphnia nauplii. It is advisable to supplement their diet with specific pellets for bottom fish such as animal and vegetable protein pellets.
You can try giving them the following vegetables to give them a varied diet, zucchini, cucumber, boiled and peeled peas, and boiled spinach, for example.
- Due to their tiny size, the size of the food given should fit the size of their mouths.
- Corydoras are nocturnal fish, so the best time to feed them is probably at night before lights out and they have to be fed once a day only.
- It is important to ensure that they get enough food, and do not overfeed them by giving them more food than they can consume in 5 minutes. If there is leftover food in the aquarium, it should be removed to keep the tank clean.
Its life expectancy in captivity is 2 to 3 years, and to keep them healthy throughout its life cycle, the most important thing is to maintain the aquarium clean effectively, since infections tend to proliferate in dirty environments.
It is important to provide them with a healthy diet so that their immune system is not weakened, since if the fish are weak, it is difficult for them to fight off diseases.
For maintenance, it is important to clean the algae and keep it under control, perform water changes every two weeks, and make weekly water tests to quickly detect changes in water conditions and correct them effectively.
On rare occasions, corydoras may be seen coming to the surface to get some air. This is quite normal, as long as it’s not frequent, and you don’t need to worry about the oxygen levels in your tank, but it may be wise to cover the tank if they do jump.
For their general well-being and to simulate the natural habitat, the light must be very dim and diffuse in the aquarium.
Pygmy Cory is highly vulnerable to red spot disease, which occurs when fish are stressed by environmental conditions, and is manifested by bloody sores especially on the belly and on other parts of the body.
One of the reasons that seem to cause this disease is the low level of oxygen in the water, so frequent water tests are essential to detect the changes.
Expert Tip: Another common ailment is white spot disease, known as Ich. It develops as white spots on the fins and body produced by an ectoparasite. It can appear when introducing new fish into the aquarium or having dirty equipment.
It can be prevented by thoroughly cleaning equipment, both new and used, and if new fish are purchased, keeping them in quarantine before introducing them into the aquarium.
To start breeding them the main thing is to check the sex of the fish in the aquarium since it is obviously important to figure out that the population has males and females. To try to reproduce corydoras, a ratio of 2 or 3 males for each female should be achieved.
The differences between the sexes can be easily perceived and can be checked by looking at the fish from above. Females are slightly larger, and their bodies are broader and rounder. On the other hand, males usually have slightly larger pectoral fins.
In the wild, corydoras typically spawn during the rainy season, and in captivity, you can encourage mating by simulating these conditions. If the fish are ready to spawn, reproduction begins with a general excitement that can be figured out when one or two males chase a female.
If a female is receptive, she will allow the male to pet her with his barbels, and they will mate in the T position. The female holds the eggs with her pelvic fins while the male fertilizes them.
If you begin to notice that the corydoras perform behaviors related to spawning, a change is first made in the temperature of the aquarium water, raising it to about 27 or 28° C to subsequently make a large change of water accompanied by a drop in temperature of three or four degrees.
After mating, the female will scatter the eggs in groups throughout the aquarium, on the glass, or between the leaves of plants, often in an area where the flow of water is quite high. They usually lay between 50 to 100 eggs, and after the female has placed them around the tank, she will ignore them.
Once the eggs are in the aquarium, it is necessary to separate them from the adult fish, otherwise, they will eat them. It is necessary to set up a breeding tank separate from the main tank, where the conditions are kept as similar as possible to the main tank.
If possible, the new container should have the same water as the spawning tank and be equally well oxygenated.
There are two ways to separate the eggs: One is that when the fish are noticed spawning, the female corydoras are moved to the new breeding tank. Once the females have laid their eggs in the tank, they are returned to the main tank, to let the eggs hatch undisturbed.
The other way is to bring the eggs to the new tank to hatch and breed after the females have laid them. If they have laid the eggs on the plants, the plants can be transferred, preferably taking care not to remove the entire plant, only the parts with eggs can be cut and moved.
If the eggs are on the side of the tank, they can be removed by running the fingers over them. The eggs are sturdy, and they won’t be hurt at all by removing them in this way.
The eggs should hatch in 3 to 5 days and the fry will be born. They will be able to survive in their yolk sac until they begin to swim freely.
Once the yolk sac is reabsorbed, it can be fed with infusoria, and when they reach sufficient size, with artemia nauplii or decomposing plant material. After about a week, they can start eating Panagrellus redivivus.
Is pygmy cory suitable for your aquarium?
They are easy to feed, care for and reproduce. This makes them a popular choice for people just starting out with aquariums. Their size and gracefulness make them attractive to the eye. and by feeding on the bottom of the aquarium they also help to clean the tank, since they find their food in the substrate.
It is a very peaceful and gregarious fish, ideal to keep in community aquariums since it can live together with almost all species, although larger fish easily intimidates it and does not know how to defend themselves or protect their food.
Expert Tip: It is advisable to keep them in groups of more than 12 individuals, and not to mix them with larger fish such as larger catfish, gouramis, or angelfish that can attack them or use them as food.
The ideal is to keep the school alone, or in coexistence with other small species, such as equally sized cyprinids or freshwater shrimps, and other dwarf cichlids as it tends to inhabit the middle levels of the aquarium.
These little fish are an ideal addition to personal aquariums. They are not only pleasant to look at, but thanks to their peaceful nature they can interact with other fish that swim mainly in the middle part of the aquarium, and that do not compete with them for food.
With basic care, the school will be healthy and will develop properly. Likewise, creating the ideal habitat within the aquarium creates a replica of their natural habitat, which will allow them to hide, swim in the shallows, and rest on the leaves and stems at the bottom.
These fish with a silvery, elongated, and thin body are the smallest specimen of the Corydoras genus, reaching a maximum length of 3 cm. Originally from the Amazon basin, they are social fish, which are comfortable in groups and communicate on the same frequency creating a school unit.
This communication is fundamental in the breeding of fry since through this communication they learn to behave, likewise it influences the mimicry of the behavior of adult fish.
To create an ideal aquarium for its development, it is important to set up a balanced relationship between the sediment sand, avoiding including stones or abrasive sand, and a proportion of stems so they can hide, and vegetation to rest.
The well-oxygenated water in the tank must have a neutral PH with an average temperature of 23 degrees. They are animals that are very susceptible to high levels of ammonia and nitrate, so to prevent them from weakening and manifesting diseases, it is essential to test the water often, as well as to change the tank every two weeks.
They are omnivorous fish, in captivity they will feed on practically any food that is supplied to them and is found on the substrate, taking special care that the food has the proper size for their mouth and that sinks since they feed by digging the sand.
They need varied and extra nutrients, they can be given animal and vegetable protein pills in small pieces, and small live or frozen animals can be included, which will help them have a more vibrant color and better health.
They are relatively easy to reproduce, it should be considered to prepare a breeding tank that keeps the same water qualities as the main tank to separate the eggs from the parents, otherwise, they will eat them.
Once the fry is more developed, they will be able to join with the adult specimens to learn from them how to feed and behave within the school. Are you thinking of including Pygmy Cory in your aquarium? If you have questions or comments let us know in the comments.
These small fish are ideal for all sizes of an aquarium, they are pacific and easy to care for, whether you are experienced or a veteran with aquariums. It is a pleasure to watch them swim close to the substrate in a school, look for food by sucking up the sand, and spend some time watching them hide and rest on the stems.