Pygmy Cory Catfish (Corydoras pygmaeus) are a delightful addition to any freshwater aquarium. These adorable, peaceful, and non-aggressive fish are known for their small size and unique behavior. This comprehensive guide will provide you with everything you need to know about Pygmy Cory care and diet, ensuring a thriving and entertaining aquatic environment.
Introduction to Pygmy Corydoras
The Pygmy corydoras, or Pygmy catfish, is a tropical freshwater fish belonging to the family Callichthyidae. 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. Native to South America, this species is commonly found in the slow-moving rivers and tributaries of the Amazon Basin, specifically throughout the Madeira River, the Nanay River, and the Aguarico River.
Appearance and Size
Pygmy Corys look like most Corydoras Catfish, apart from their size of course. As the name suggests, Pygmy Cories are known to be very small. These fish have a couple of defining characteristics that will help you identify them. Like others in the genus, they have a unique teardrop-shaped body with a large head. 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). 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. The black markings are the major distinguishing factor between Pygmy Cory and Corydoras hastatus. Males and females are nearly identical in appearance. The only main difference is size. Females tend to be a bit bigger.
Lifespan
The Pygmy Cory has a relatively short lifespan. Pygmy Cory Catfish can live for up to 4 years. Of course, there are no guarantees when it comes to lifespan. There’s a certain degree of luck involved.
Tank Setup and Water Conditions
The best thing about keeping Pygmy Corys is that you don’t need much in the way of tank size! Unlike every other species of Corydora Catfish that require a 20 Gallon Long tank or 29 Gallon Tall tank, Pygmy Cories require a minimum tank size of 10 US Gallons! A 10-gallon (40 liters) tank should be enough for housing 4 - 10 pygmies. When choosing a tank, select one that’s longer than it is tall.
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Mimicking the Pygmy Cory’s natural habitat is always going to yield the best results. These fish live in rivers and tributaries throughout South America. The flow of water is moderate, providing them with plenty of resistance (but nothing too crazy). The water is often enriched with tannins, which facilitates a slightly acidic environment as well. The Pygmy Cory Catfish has a narrow range of comfort compared to other fish. As a result, it’s important to keep monitor conditions regularly to avoid undue stress. Because of this narrow window you need to maintain, it’s essential for you to invest in a reliable and accurate water test kit for your aquarium.
Substrate and Decor
This fish species appreciates fine-grained substrates for their daily life. A sand / fine gravel substrate without sharp edges (!) is best suited for this purpose. Finally, like all Corydora Catfish, Pygmies have sensitive barbels on their mouths that are easily damaged. With out their barbels the Cory will die. To prevent this it is recommended to use fine substrate such as sand or a VERY fine gravel to prevent Barbel Damage.
Like any other fish, Pygmy Corydoras do best when kept in a natural-looking environment that stimulates their native habitat. Start by creating a safe foundation for these fish. Pygmy Corydoras will spend a lot of time searching for food on the lower part of the water column. To keep their delicate barbels safe, avoid gravel or rocks. The sand is safe, helping the fish avoid unnecessary injuries. Next, add plants and driftwood. Keep things natural and varied. Add tall background plants, floating plants, and small foreground plants. They prefer tanks with dense vegetation, including plants like Amazon Swords or Cryptocoryne, providing cover and shelter. These fish are particularly fond of grasses and shrimp flats as well. Pygmy Corydoras do prefer to be in heavily planted tanks that have good water quality. The tank can be set up in an Amazonian biotope style. 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.
Water Parameters
Hardness: Soft water is preferable. Maintain the water temperature between 22-27°C (71.6-80.6°F) with a pH range of 6-7.8 and water hardness between 4-20°N (71.43-357.14 ppm).
Lighting
Lighting: Pygmy Cory catfish prefers dim-medium lighting conditions. They tend to exhibit increased activity levels in the presence of high lighting which stresses them out.
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Filtration
Because of their small size, pay special attention to the filtration equipment. If you have large inlet tubes, consider adding sponges to prevent accidents.
Diet and Feeding
Feeding Pygmy Cory is no biggy. In the wild, they nibble on micro food available within their reach. Pygmies are omnivores, and as such, they will appreciate plant food equally. As a whole, Pygmy Corydoras are very peaceful. They’re not known for exhibiting any signs of aggression. Most fish will spend their time hiding and playing in plants. While they spend a lot of time on the bottom of the tank, Pygmy Corys like to occupy the middle of the water column most.
Choices may range from algae wafers, sinking catfish pellets to commercially prepared green food. 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. Some supplemental foods to give your Pygmy Corydoras may include blanched zucchini, spinach, peas, and cucumber. Dwarf Corydoras are small and require food suited to their size. Use high-quality flakes and small sinking pellets as their staple diet. They will happily accept live and frozen foods, such as bloodworms and microworms. For added variety, offer broken-up algae wafers to meet their nutritional needs. Algae Wafers, Frozen, Live, and Flake food are accepted readily by Pygmies. Note: Pygmy Corydoras are primarily meat eaters and should not be fed AW as a staple.
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. There are some ways to solve this problem. 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.
Tank Mates
Pygmy Cories are peaceful fish that may be easily intimidated by larger tankmates. They will appreciate the presence of other small-sized fish with the same temperament as tankmates. Due to this Corydora's peaceful nature they are compatible with most other peaceful community top, bottom dwellers, and will never be the bully of the tank. But, larger fish may pick on them. Nevertheless, there are a whole lot of potential tankmates out there to consider. Be very careful with Betta, Paradise fish, Siamese Algae Eater, and Angelfish. Some tank mates to avoid are Cichlids, Goldfish, Jack Dempsey, and Oscars.
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The Pygmy Cory needs a shoaling group to stay healthy. When kept alone, they fall prey to the unhealthy symptoms of stress. Author Note: Keeping a Pygmy Cory with a betta fish is not something we recommend.
Compatibility with Invertebrates
Pygmy Cories are compatible with any freshwater snail. Although Pygmy Cories are not hunters, they are still omnivores. 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. I would say that Pygmy Cory is the second-best shrimp safe fish after Otocinclus. Absolutely not! Keep them away from all types of crayfish and crabs.
Tank Maintenance
Pygmies are not very tolerant of high levels of ammonia, nitrites, and nitrates. In light of the aforementioned, you will have to change 10-25 % of their water periodically. Another thing to be conscious of is the bacteria levels in the substrate. 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.
Breeding
Breeding Dwarf Corydoras is relatively straightforward, especially when kept in well-maintained conditions. During spawning, they scatter their eggs across plants and the tank glass, often placing the eggs separately rather than in clusters. To encourage breeding, perform regular water changes and maintain soft, slightly acidic water. The eggs usually hatch within 3-5 days. Due to their tiny size, the fry should be fed newly hatched brine shrimp or finely crushed flake food.
As observed, breeding in this fish species is a bit technical. However, it is easier to attempt the reproduction of pygmies in a dedicated tank different from the main one. Breeding is acheived in a 10 Gallon tank dedicated to breeding Pygmies by obtaining more Males per female. Preferably 2M:1F. The females will look noticeably larger and plumper when they are ready to breed. 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 the water flow is high. The couple repeats this process until around 100 eggs are fertilized and attached. Some experienced aquarists simulate natural processes in order to get better results (for example, in fewer infertile eggs). 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’. Also, peat filtration is suggested in order to produce soft acidic water. Note: However, if you are a beginner or simply do not want to jump through hoops to get the optimal breeding rate.
Females will hold onto a few eggs at a time and wait for the male to fertilize them. Once done, she’ll deposit them on a smooth surface. Once she’s done, remove all of the adult fish. As the eggs develop over the next few days, watch them closely. Before you know it, the fry will emerge. The baby fish will eat the egg sac until they are free-swimming.
Common Diseases and Health Issues
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 the health / immune system of the fish to fend diseases off.
Pygmy Corydoras can experience stress when water conditions become unstable. Pygmy Corys are susceptible to all the usual freshwater ailments. However, the Pygmy Cory Catfish is thought to be more susceptible to a condition called red blotch disease. This disease is typically a byproduct of stress.
- 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.
- Costia: This is a parasite a.k.a Ichthyobodo (protozoa) which thrives in cold water and is often difficult to detect in the early stages. Symptoms include red, grey/white patches on the skin, clamped fins, loss of appetite, and itchiness.
- 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. This infection can be treated with a broad-spectrum antibacterial medication.
Unique Behaviors
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. This species is capable of using its intestines to take up oxygen! Pygmy Cories, and all Cories, have the ability to breath from the surface of the air. This behavior is perfectly normal. But if it becomes a regular thing, it may be a sign of poor water conditions. C. Pygmaeus are not the traditional bottom dweller. Pygmy Cories are a part of the "armoured" catfish group.