Sometimes it is the smaller things in life that give us the most joy.
If you have been searching for the perfect fish to add to your aquarium then the Pygmy Cory might just be it.
These peaceful little catfish are native to South America and are best known for their small size. Their size automatically classifies them as nano fish.
They are perfect for beginners and do not require as much hard work as other species.
Are you interested in learning more about them?
Keep reading to find out everything you need to know about them including tank setup, feeding needs and how to tell the difference between the Dwarf Cory and Pygmy Cory…
Table of Contents
What is a Pygmy Cory?
The Pygmy Cory, short for Pygmy Corydoras, is a small species of freshwater catfish from the family Callichthyidae. Their scientific name is Corydoras pygmaeus and they are native to South America and tend to be found in Ecuador and Brazil.
This is a peaceful and incredibly sociable fish.
They tend to shoal in groups and get along with a large variety of smaller fish. Their small size means they do not require a huge amount of space which may be perfect if you have a small budget.
The Pygmy Cory looks like a little nugget of silver.
It is fun to watch them as they interact with each other, play-fighting or hiding among plants and objects at the bottom of the tank. There is no doubt that they have quite a big personality for such a tiny fish.
They normally live up to 3 years and will cost around $2 per fish.
- Experience Required: Beginner.
- Nicknames: Pygmy Corydoras, Pygmy Catfish, Pygmy Fish.
- Color Forms: Silver with a solid black horizontal stripe across their body.
- Size: 0.75-1.2 inches.
- Tank Size: Minimum 10+ gallon.
- Tank Temperature: 72-79°F.
Pros and Cons
- Do not need a big tank
- Peaceful temperament
- Omnivorous so they are not picky eaters
- Very good tank mates
- Susceptible to red blotch disease
- Caring for fry can be difficult
- Should not be kept with bigger fish
Appearance and Size
The Pygmy Cory is known for its shimmery silver body with a classic black horizontal line extending from the snout to the caudal fin. The line becomes more oval-shaped and wider towards the end.
There may be slightly lighter black lines towards the lower body which generally ends in a cream-white belly. These lines tend to run from the anal to abdominal fin.
The upper portion of their body tends to be a darker shade of grey.
Their silvery tone will shimmer as they swim through your tank.
These catfish have a body shape that resembles a tear drop, along with a slightly large head.
Their mouth which is under-turned also contains sensory barbels which help them forage for food. In the wild they are occasionally bottom-dwellers, lurking among the deeper depths of the rivers so having this adaptation is key for feeding.
Males tend to be smaller at around 0.75 inches long. The females will be larger and broader (especially when they are carrying their eggs) at around 1 inch long. It can be quite difficult to determine the gender of this fish, but one trick is to look at the fish from above- if it is more bulbous it is female.
Habitat and Aquarium
In the wild the Pygmy Cory often inhabits slow-moving freshwater rivers which tend to be clear and full of light.
However the water conditions tend to vary as some areas may be more turbid (cloudy with suspended sediment) or have even slower or faster flows.
For example in the Rio Madeira Basin where they are often found, the water is filled with sediment and tends to be murky. The pH as well as the temperature of the water will vary too but will be warm in these tropical areas.
A 10-gallon aquarium is more than enough for 4-6 Pygmies.
It is also important to remember to add at least 2 gallons for each individual.
When setting up your aquarium the water conditions need to replicate that of their natural tropical environment.
A temperature range of 72-79°F with a pH of 6.5-7.5 is ideal.
Pygmy Corys prefer slightly acidic and soft conditions in the long term so it is best to keep the pH a little on the acidic side but close to neutral. This can be done through peat filtration. It is important to keep the tank conditions as ideal as possible. Pygmy Corys have a very narrow preference range which means that they are comfortable only in very specific conditions.
There needs to be plenty of light in the tank in order to replicate their natural conditions, but since both light and turbidity vary (turbidity can reduce light levels) it is best to keep the lighting dim to medium.
The only other piece of equipment needed is an efficient filter. Because they are tiny, you should make sure the output of the filter is slow and that the inlet tubes are not too big.
Soft sandy silt substrate is very important too. They have very sensitive barbels around their mouth so if rocks or gravel are used, it could damage these sensory structures.
When it comes to designing your tank you should avoid over crowding it.
In the wild these fish tend to hide near dislodged branches and root structures at riverbanks. They also tend to shoal in groups of at least eight around the bottom to middle water layer so careful planning of tank decoration is vital.
Include lots of stimulating objects such as plants, clay pots and driftwood. Plants should have wide leaves which provide a space for the little catfish to relax.
The Pygmy Cory is a fairly healthy fish.
However they are prone to Red blotch disease. The main symptoms of this ailment are red, bloody sores that break out all over the fish’s body (usually on the belly). This will usually occur under stressful environmental conditions which is why it is very important to make sure that the water tank conditions are up to standard.
It is thought to be caused by very low oxygen content in the water so make sure water changes are performed weekly.
Another disease that Pygmy Corys are susceptible to in poor conditions is ich.
Ich disease is a common infection caused by an ectoparasite. It causes white spots to appear on the body and fins. Other symptoms may include gasping for air and rubbing against objects in the tank and loss of appetite.
It often spreads through the addition of a new fish or second-hand equipment that is not cleaned properly. This disease is very easy to treat but make sure to quarantine any new fish and thoroughly clean any equipment before it is introduced into the tank.
You also need to make sure that their diet is healthy and balanced.
There is a popular belief that Pygmy Corys only eat algae – this is a myth. Pygmy Corys are omnivores and require a balanced amounts of meat and plants. A diet only containing dried food does not contain all the nutrients that a healthy and happy Pygmy needs.
Feeding and Diet
In the wild these fish will eat small micro-foods that cross their paths when they are swimming around the bottom of the river.
They are natural omnivores so they eat plants, vegetables, and meat.
Pygmy Corys will eat anything from algae pellets to meaty brine shrimp. They also tend to be bottom-feeders which means that anything that can sink to the bottom of the tank is a good pick.
Their mouths are incredibly small so they can only fit items smaller than they are. The portions of the food should be very small to allow them to eat as much as they can without struggling. If you are offering them fresh food such as chopped up vegetables or shrimp, make sure it is small enough for them.
Sinking foods such as algae wafers and catfish pellets are great options.
Pygmy Corys do not require any special supplements as long as their diet is nutritious. Feeding them solely dried or plant-based food will not provide them with all the nutrients they need which is why it is a good idea to add some meat snacks too.
Meat options include: bloodworms, white mosquito larvae, baby brine shrimp, tubifex worms and daphnia. If you do want to go for the cheaper options then dried flakes, micro-granules, frozen and dried foods will still be a tasty treat.
Feeding time should take around 2 minutes and they should be fed twice a day.
Make sure to watch during feeding time because lots of species can snatch any sinking food before it has time to reach the bottom. Keep a close eye on the sinking pellets and make sure they reach your Pygmy Cory.
One of the most unique behaviors you will watch Pygmy Corys perform is an occasional swim to the surface to gulp air.
They have a modified vascular system which allows them to carry out intestinal respiration. This means that they can take in oxygen from the air using their intestines. This behavior is carried out when the water quality is poor and especially when oxygen levels are low.
If you notice them swimming to the surface often then it could indicate that the water conditions are not as good as they should be.
They are schooling fish and will school in groups ranging from 3 to 10. It is quite rare to see catfish swim together at higher water levels which is what makes them even more unique.
Schooling lets individuals within the group understand and familiarize themselves with the behavior of each other. In the wild this is important as the behavior of individuals can be assessed in different contexts such as defense or feeding. This allows species to create a stable structure within the group to maximize survival.
These peaceful and tranquil catfish do not display any aggressive behaviors so are the perfect addition if you are looking for safe tank mates. They may even play-fight and chase each other in their groups to develop a better social bond.
They tend to occupy the middle levels of the tank but are also occasionally found hiding at the bottom near big plants.
These sociable fish are very calm and well-behaved.
They will get along with just about any fish and in the wild you can find them with lots of other fish species, especially bottom-dwellers. This is no surprise as tropical freshwater rivers are home to a variety of species.
Many of these species will belong to the Callichthyidae family such as the Corydoras similis.
Some of the best tank mates are:
- Cherry Barb
- Chinese Algae Eater
- Kuhli Loach
- Zebra Danio
- Neon Tetra
- Dwarf Gourami
- Red Cherry Shrimp
- Bamboo Shrimp
- Amano Shrimp
Of course you could also keep other Pygmy Corys.
In the wild these fish tend to shoal in small schools of around 8. They are not territorial and are not aggressive to each other so there is nothing stopping you from keeping a school.
Just remember that any species of bigger fish should be avoided as there is a risk that little catfish could become a quick snack. You should also avoid small but aggressive fish which can cause them to get stressed.
Breeding these fish is relatively easy but raising the fry can be difficult.
Pygmy Corys breed quite regularly on their own providing they have a healthy diet and their tank conditions are set up correctly.
The more fish in the group the more likely they are to breed. A ratio of 2 males for every female is enough to start breeding.
You can start by feeding them a heavy protein diet and slightly increase the water temperature in the tank by 2-3 degrees. Slightly acidic conditions may also be useful for breeding. This is thought to replicate the changes in environmental conditions in the wild.
Females will lay up to 100 eggs and will hold some of these eggs in a small pouch near the pelvic fin for fertilization.
A pair will assemble into a T shape and the male will release its milt to fertilize the eggs.
After fertilization the eggs will be deposited onto a safe smooth surface that the female cleans such as the walls of the tank or thin-leaved plant. They will then hatch.
It is important to note that the parents are likely to eat their eggs as well as the offspring once they hatch so they should be separated from the eggs.
After 3-5 days the eggs will hatch and the fry will eat their yolk sacs and become free-swimming. Since the fry are so small they should be fed a specialized diet including infusoria, crushed flakes and microworms until they are big enough to start an adult diet.
History and First Sighting
The Pygmy Cory was discovered in the early 1900s.
It was first recognized after a misidentification of the Corydoras species.
There was thought to be only one of the Corydoras species; the Dwarf Cory (Corydoras hastatus). Since they looked very similar to the Pygmy Cory and other Corydoras species it was hard to distinguish between the species. After this realization, the Pygmy Cory species was described and identified.
The first published description was released in 1966 by Joachim Knaack.
Little is known about how this species became captive-bred from the wild and much of the information on the history of these species points to the misidentification of both the Pygmy Cory and other Corydoras species.
However since they have been recognized as their own species their popularity has risen over decades and they have become a well-loved species.
Pygmy Cory vs Dwarf Cory
It is common to see the names Pygmy Cory and Dwarf Cory used interchangeably to describe either species, however they are actually two different species of the Corydoradinae sub-family.
The scientific name of the Dwarf Cory is Corydoras hastatus but they also go by their common name; the tail-spot Cory.
They are called this because of the distinctive dark spot on their tail with a white border. They do also have a silvery body, but their dark horizontal lines are much lighter than those of the Pygmy Cory.
These species do share similarities in behavior too, as well as care requirements such as tank size, temperature, and pH conditions. They are a similar size and are native to the same regions with the Dwarf Cory endemic to Paraguay and Brazil. These similarities means that the Pygmy and Dwarf Cory can easily be put in the same tank together.
Just make sure to check the identity of these species when you buy them as they can be mislabeled in many pet stores.
Facts about Pygmy Cory
|Other Common Names:||Pygmy Corydoras, Pygmy Catfish, Pygmy Fish|
|Scientific Name:||Corydoras pygmaeus|
|Color:||Silver with solid black horizontal stripe across body|
|Minimum Tank Size:||10 gallons|
|Tank Mate Compatibility:||Sociable with most species|
If you are looking to create a relaxing and tranquil community tank then the Pygmy Cory is worth considering.
These non-demanding nano fish are low-maintenance and will be very content in a school. All they require is good water quality, suitable temperature and pH conditions and many plants and objects to stimulate their curiosity.
Their tiny size means you can keep them in a small 10-gallon tank easily.
Are these the silver bullets that you have been looking for?
Let us know if the Pygmy Cory has caught your eye in the comments section below…