Pygmy Cory – Detailed Guide: Care, Diet, and Breeding

Pygmy Cory Catfish (Corydoras pygmaeus)

Today, we will be talking about Pygmy Cory Catfish (Corydoras pygmaeus). Pygmy Cory is a peaceful and miniature fish species commonly found in freshwater aquariums, they are quite popular in the hobby and due to this reason you can easily find them in pet stores retailing for as low as $2.

Do you know that Pygmy Cory Catfish can live for up to 4 years? That’s great if you ask me. Keep on reading for more information about this fascinating fish species; we will discuss its appearance, care, breeding amongst others.

Quick Notes about Pygmy Cory

Name Pygmy Cory
Other Names Dwarf catfish, Micro catfish, Pygmy corydoras
Scientific Name Corydoras pygmaeus
Tank size (minimum) 10 gallons (~40 liters)
Keeping Easy
Breeding Easy
Size up to 3 cm (~ 1.5 inches)
Optimal Temperature 22 – 26 °C (72 – 79 °F)
Optimal PH 6.5 – 6.9 (6.0 – 8.0) 
Optimal GH 4 – 16   
Optimal KH 2 – 8
Dwellers Mid and bottom
Nitrate Less than 20
Diet Omnivore
Temperament Peaceful
Life span up to 4 years
Color Form Silver in color with one black line

Origins of Pygmy Cory

The Pygmy corydoras or Pygmy catfish is a tropical and freshwater fish belonging to the family Callichthyidae. This fish species originates in tropical inland waters in South America and is commonly found in Madeira River basin in Brazil.

The first scientific description of the fish species – Corydoras pygmaeus was published in 1966 by German biologist and physician Joachim Knaack. This fish species was placed in the genus Corydoras. The scientific name uses the Latin word pygmaeus which implies dwarf or pygmy. Corydoras pygmaeus is commonly known as Pygmy Corydoras (Pygmy Cory) and Pygmy Catfish. Corydoras pygmaeus is often mistaken for Corydoras hastatus; this is because at one point, hastatus was the only known miniature Corydoras species. 

Natural Habitat of Pygmy Cory

Pygmy Cory is native to South America and they are widely distributed in inland waters: in Peru- in tributaries of the Nanay River, in Ecuador- in tributaries of the Aguarico River, and predominantly in Western Brazil – in tributaries of the Madeira River.

In nature, they can be found in large numbers hiding in tree roots, marginal vegetation, and creeks. 

Pygmy Cory Description

Pygmy Cory Catfish (Corydoras ) pygmaeus) schoolingPygmy Cory looks like most Corydoras Catfish, apart from their size of course. As the name suggests, Pygmy Cories are known to be very small. Females tend to range from 1 – 1.3 inches (2.5 – 3.2 cm) long whereas their male counterparts are even smaller, reaching just 0.75 inches (~2 cm). Moreover, the females are rounder and broader especially when full of eggs.

The body of Pygmy Cory is adorned by a silver coloration with a solid black line that runs horizontally all the way from the snout to the tail fin. This is accompanied by another thinner black line that runs lower down the body. Its upper part is visibly darker than the lower part.

Newly hatched fry possess vertical stripes on their sides, these will gradually fade to be replaced by the horizontal stripes at the end of their first month.

The black markings are the major distinguishing factor between Pygmy Cory and Corydoras hastatus. Also, hastatus has black shades on their tails that resemble black arrowhead which the Pygmy Cory lacks.

Pygmy Cory Behavior

Pygmy Cory Catfish (Corydoras pygmaeus) and plantsPygmy Cories are adorable, peaceful, non-aggressive, and very shy fish, they are best kept in a community tank of non-aggressive and small fish species. They are usually kept in groups of at least 6 and even better in larger groups of preferably 10 or more (more is always better). They love swimming in shoals around the mid and lower levels of the tank.

Although the fish is generally a mid-water dweller, they will occasionally move downwards to burrow into the substrate. Therefore, a fine-grained substrate should be adequately provided so that the fish won’t harm its barbels in the process.

Corys are facultative air breathers by nature, this means that they have the ability to breathe atmospheric air when necessary. They have a modified, highly vascularised intestine which aids the intake of oxygen from the air.

This adaptive feature helps them to survive if their habitat becomes oxygen-deprived for any reason. Occasionally, in the aquarium, you will see them swimming up to the surface to take in gulps of air. Their visits to the surface of the water will be more frequent if poor water conditions exist in the tank.

Features:

  • Social: Very
  • Active: Yes
  • Peaceful: Yes 

Feeding Pygmy Cory

Feeding Pygmy Cory is no biggy. In the wild, they nibble on micro food available within their reach. Whereas, in the aquarium, you can feed them a wide variety of meals such as:

  • brine shrimp (artemia salina),
  • bloodworms,
  • grindal worms.

If you don’t fancy live food, you can explore other options like:

  • frozen bloodworms,
  • mosquito larvae,
  • freeze dried tubifex & black worms.

Pygmies are omnivores, and as such they will appreciate plant food equally. Choices may range from the algae wafers, sinking catfish pellets (link to check the price on Amazon) to commercially prepared green food. This fish species will have no problem taking any kind of food as far as the food offered is small enough to fit into its mouth for mastication and digestion.

They also like a natural layer of decaying leaf litter. It may not look very attractive but adding some variety to the diet will improve their immune system as well. So, provide them with some Indian almond leaves, alder cones, etc.

Some supplemental foods to give your Pygmy Corydoras may include blanched zucchini, spinach, peas, and cucumber. Make sure that all vegetables added to a tank should be verified as pesticide-free.

Important: Pygmy Cory is not an aggressive eater. Therefore, if you have other fish species in the tank, it can be difficult to keep them fed. They often avoid jumping into the food when there are too many other fish.
There are some ways to solve this problem. For example, it can be spot feeding them by using small pipes or adding their food after dark.

Features:

  • Diet Type: Omnivore
  • Food Preference: Algae
  • Feeding Frequency: Daily

You can read more about it in my articles:

How to Blanch Сucumbers and Zucchini for Shrimp, Snails and Fish the Right Way
Indian Almond Leaves and Alder Cones in a Shrimp Tank.

Are Pygmy Corydoras Plants Safe?

Pygmy Cory Catfish (Corydoras pygmaeus) resting on plantYes, Pygmy Corydoras are completely plant safe. They will not eat any healthy plant in the tank. They simply do not eat healthy, living plant material.

Plants like mosses will also greatly benefit them. The structure of the plan acts like a spider web, it catches all the free-floating particles. Therefore, it creates a natural feeding ground for the Pygmy Corydoras as they are small they can get into places bigger fish cannot. Therefore, they will be often grazing on moss.

Note: Plants with large leaves in the lower half on the tank will be a great hammock for them to rest and sleep on. 

Keeping and Housing Pygmy Cory

Pygmies are not very tolerant of high levels of ammonia, nitrites and nitrates. Therefore, before introducing your pygmies, your tank should be cycled and fully established.

In light of the aforementioned, you will have to change 10-25 % of their water periodically. However, water changes should be done once or twice monthly because pygmies don’t do so well when there is a frequent change in water chemistry.

Another thing to be conscious of is the bacteria levels in the substrate. Pygmy Cory catfish is hugely plagued by bacteria infections, therefore, you should take proper preventive measures to curtail it.

Ensure that you perform routine water tests, clean up leftover food, and get rid of dead or decaying plant matter by cleaning and vacuuming the substrate. Furthermore, ensure that there is proper circulation of the tank water so that biofilm will not accumulate on the water column because this can disrupt their breathing. 

Tank Size:

A 10-gallon (40 liters) tank should be enough for housing 4 – 10 pygmies. If you want a larger group of catfish, then you would be needing a tank with higher capacity.

Water Parameters:

Temperature: An optimal temperature range of 22 – 26° C (72 – 79° F) should be maintained always.

pH: Although, they can adapt to a pH range between 6.0 – 8.0, Pygmy Cories will thrive best in slightly acidic waters under pH values between 6.5 – 6.9.

Hardness: Soft water is preferable. The corydoras can tolerate neutral or slightly hard water conditions between 2-15 dkH., but it does not mean that they will thrive and be happy.

Lighting: Pygmy Cory catfish prefers dim-medium lighting condition. They tend to exhibit increased activity levels in the presence of high lighting which stresses them out. Floating plants like Duckweed can be used to diffuse bright lighting within the tank. 

Substrate:

This fish species appreciates fine-grained substrates for their daily life. A sand / fine gravel substrate without the sharp edges (!) is best suited for this purpose. It will protect your fish against scratching their delicate sensory barbels when searching for food in the substrate.

Note: Personally, between sand and small, round gravel, I would always choose sand.

Plants and Decorations:

Pygmy Corydoras do prefer to be in heavily planted tanks that have good water quality. Barely decorated tanks without live plants will be very stressful and unpleasant for them.

The tank can be set up in an Amazonian biotope style. Use a fine sand substrate in addition to some aqua soil, add few driftwood branches, broad-leaved plants, and twisted roots so as to replicate their natural home.

Basic Tank Equipment (links to check the price on Amazon)

Breeding Pygmy Cory

Pygmy Cory Catfish (Corydoras pygmaeus) laying eggsAs observed, breeding in this fish species is a bit technical. However, it is easier to attempt reproduction of pygmies in a dedicated tank different from the main. Here, the water parameters of the main tank should be replicated in the new tank and sponge filter should be used in place of a canister filter to avoid sucking the fry.

The females will look noticeably larger and plumper when they are ready to breed. Cory catfish stocking in a ratio of 2 males to every female produces the best results.

The female usually holds a few eggs between her pelvic fins, where the male fertilizes them. After each spawning, the female will deposit eggs on the tank glass, often in an area where water flow is high. The couple repeats this process until around 100 eggs are fertilized and attached. These eggs will hatch after 3 – 5 days.

Advanced Methods to Breed Pygmy Cory

Some experienced aquarists simulate natural processes in order to get better results (for example, in fewer infertile eggs). To do so:

  • A cooler water change (10ºF (5.5ºC)) is recommended in order to trigger your fish (male and female) into spawning in the classic ‘t -position’. However, if your water temperature is already in the low to mid-70s F (22º to 25ºC), there is not a need to lower the temperature further.
  • Also, peat filtration is suggested in order to produce soft acidic water. In nature, this is a sign of the rainy season.
  • Adding more airstones will simulate the stormy flow.

Note: However, if you are a beginner or simply do not want to jump through hoops to get the optimal breeding rate. I can assure you that, eventually, Pygmy Cories will spawn successfully even without any changes in the water at all.

Although, it does not happen very often but the adult may eat these eggs if left unprotected, so you should either remove the eggs from the tank into a new container or move the mature fish instead.

Also, the eggs might develop fungus in the tank, but this can be combated by adding methylene blue to the tank water and removing bad eggs in order to protect the healthy ones from possible infection.

Feeding Pygmy Cories Fry

Pygmy Cory Catfish (Corydoras pygmaeus) fryAt the early stages, the fry are almost invisible and they will absorb their yolk sac for survival.

Even though Pygmy Cories fry can eat the same foods as adults, it is better to focus on:

  • hatched brine shrimp,
  • microworms,
  • finely crushed flakes

Tip: You can also squeeze filter media to get them feeding.

If you want your Pygmy Cories fry to grow fast, you need to feed them 2 times a day and also do 50% water changes 2 times a week. This way they will almost halve of the inch (1.5 cm) long only in 2 months. 

Problems associated with Pygmy Cory

While taking care of Pygmy Cory, you shouldn’t strike out the possibility of running into a number of diseases or health conditions. Routine tank maintenance practices will help to combat these conditions, while proper feeding will boost health / immune system of the fish to fend diseases off. Some of these diseases include the following:

Skin & Gill flukes: These are worm-like parasites that attach to your fish. On physical inspection, you might have a hard time diagnosing these flukes since they are very small and almost invisible to the human eye. This disease is caused by overcrowding, high-stress levels, and bad water parameters. The common symptoms are: Itchiness, excess mucus in skin, and redness in skin and gills.

Costia: This is a parasite a.k.a Ichthyobodo (a protozoa) which thrives in cold water and often difficult to detect in the early stages. Symptoms include: red, grey/white patches on the skin, clamped fins, loss of appetite, and itchiness. An effective and affordable method of treating Costia is with salt; mix 3-4 grams of salt per liter of water and dip the affected fish.

Bacterial infection: Bacterial infection is caused by the presence of bacteria in the tank, it can be difficult to tell the actual bacteria causing the harm. A good example is the Red blotch disease. Symptoms include bloating, red ulcers, red streaks.

This infection can be treated with a broad-spectrum antibacterial medication. NB: Some assumed bacterial infection can actually be a fungal infection when at crossroads you can treat with Ich X and Erythromycin.

Pygmy Cory and Suitable Tankmates

Pygmy Cories are peaceful fish that may be easily intimidated by larger tankmates. Because of how their mouths structured, they do not even nip other fish and never fight back when bullied.

Fish:

They will appreciate the presence of other small-sized fish with the same temperament as tankmates. Well, if only these pygmies were larger, they would make an ideal community fish.

Nevertheless, there are a whole lot of potential tankmates out there to consider. Out of all possible suggestions, my favorites include:

Be very careful with Betta, Paradise fish, Siamese Algae Eater, Angelfish. They are like every species; some are more aggressive than others.

Some tank mates to avoid are Cichlids, Goldfish, Jack Dempsey, and Oscars. They should never be placed in a tank with Pygmy Cory.

Shrimp:

Will Pygmy Cory eat dwarf shrimp? Although Pygmy Cories are not hunters, they are still omnivores. Therefore, if baby shrimp are tiny and fit in the mouth of pygmies, there is always a chance that they will try to snack on them.

Does it happen very often? No, it is not. First of all, Pygmy Cories put their heads deep into the sand and stumble along with half-blind eyes closed. Second, shrimplets that are 1 – 2 weeks old will be too big for them to eat.

I would say that Pygmy Cory is the second-best shrimp safe fish after Otocinclus. However, if you are planning to seriously breed shrimp, you cannot allow any fish in the tank!

Snails:

Pygmy Cories are compatible with any freshwater snail. They will do a good job in scavenging for food particles, plant matter, and algae along the lower levels of the tank.

Crayfish and Crabs:

Absolutely not! Keep them away from all types of crayfish and crabs. They can and will try to catch Pygmy Cory whenever it is possible.

In Conclusion

Pygmy Corydoras is one of the best beginner fish species for nano tanks.

There are a lot of reasons to be fascinated about this fish species; top of the list is the unique behavior that they display in the tank. Also, pygmies are easy to care for, they are attractive, lively, and can coexist with a variety of species peacefully.

Pygmy Cory Catfish (Corydoras pygmaeus)

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