Cory Catfish

When people think of Corydoras Catfish (also known as Cory Catfish), they think of an algae eater, but what you might not know is that Cory Catfish are also known for their beautiful colors.  Not only do they come in a variety of vibrant colors, but they also have a variety of patterns.  These patterns tend to be thicker on the flanks and thinner on the head.

Cory Catfish are a species that’s native to South American wetlands. They are small fish, and they’re one of the most popular catfish species on the market today. Cory Catfish are a very active species of catfish. They are also known to be quite friendly towards other fish. 

One of the best things about Cory Catfish is that they can get along with most tank mates. They’re particularly nice with other species of fish, and they won’t hurt smaller fish either.

a cory catfish searching for food

Information about Cory Catfish

  • Average Length: 1 to 4 inches
  • Scale Colors: White, Green, Bronze, Black and Albino
  • Attention Needs: Low
  • Good tolerance to Heat and Cold: Yes
  • Good Pet: Yes!
  • Safe with Children: Yes
  • Good with Other Cory Catfish: Yes
  • Good with Other fish species: Yes
  • Suitable for First-Time fish Owners: Yes
  • Health Concerns: They tend to have diseases like Red Blotch and Ich.
  • Average Life Span: 5 – 7 years

Physical Appearance of Cory Catfish

Just like Plecos, Cory Catfish also has an armored body with bony plates covering most of their body. Even the fins are heavily spined which acts as a defense mechanism to protect them from predators. For this reason, they are often called ‘armored catfish.’ 

Cories have dorsal fins that are pointed upwards, giving a sail-like appearance. Some may also have rounded dorsal fins. The tail fin is fork-shaped with different species having different length and height. 

They have a short face and white eyes with a ring around it. Near the mouth, on the front of their face they have three pairs of barbels that look like whiskers. These barbels help them find food in the sand.

There are over 170 different species of Cories and the majority of them are still not named! With so many different species, Cories can come in several different color variations and patterns.

For example, the Panda Cories,  have a white or orange base with black patches around their eyes and dorsal fins. For this reason, they were named Panda Cories. On the other hand, Peppered Cory Catfish has a bronze base with black patches all over their body.

Temperament of Cory Catfish

Just like other catfish, Cories are bottom-dwelling species. While many think that the Cories are nocturnal, this is not exactly true. They may sometimes move around in the night, but mostly they are active during the day. 

Cories are a shoaling fish which means that they like to stay in a group and it is recommended to keep them in a small group of 6 or more. Staying in a group also helps them to feel secure.

They are also active and curious. Cories will spend most of their time scavenging for food close to the bottom of the tank. You may sometimes also find them staying still which seems odd but is completely normal for them.

Cory Catfish are calm and non-aggressive. They will not attack other fish. If they feel threatened, Cories will swim away to a hiding spot or use the plants to get away from the attacking fish. These qualities and more covered later make them a great choice for a community tank.

Best Habitat for Cory Catfish

Cory Catfish are hardy and easy to care for. Compared to other fish species they do not need a very large tank. All you have to do is maintain ideal water conditions inside the tank.

While setting up their tank keep in mind that Cories are very sensitive to toxic compounds like ammonia, nitrite and nitrate. Make sure you cycle the tank before introducing your fish to their new home. Cycling helps to promote the growth of beneficial bacteria that break down the compounds into less toxic ones.

Tank size

As most species of Cory Catfish are small and will not grow more than 4 inches, a 10-gallon tank is enough for a single fish. However, as mentioned before, these fish like to stay in a group, so a 20 gallons tank is needed for a group of 6. If you plan on keeping other fish species with your Cories, which you should, then a larger tank will be needed. The size of the tank will depend on the size and the type of fish you keep.

a cory catfish swimming


Cory Catfish like the temperature of the water should be in the range of 70 to 80° F. More than working towards establishing a perfect temperature, it is important to ensure that the temperature stays stable. Any sudden fluctuations can stress your fish.

Water Hardness and pH

Most Cory Catfish will need a pH level between 6 to 8 and water hardness between 3 to 10 dKH. Depending on the specific species this may slightly vary. 


Cories do not have any specific lighting needs and will do just fine with any type of lighting in the tank. At the same time, adding lights to your tank is important because other organisms like live plants and other fish species will need the light to grow. You can add LED lighting as they are efficient and will light your tank without generating a lot of heat. Cory Catfish are hardy and will adapt to them.


Live plants should be added inside the tanks as Cory Catfish love them! You can add almost any kind of plant. For beginner fish tank owners Java Fern, Java Moss or Anubias Nana are a great option as they are easy to plant and need minimum care.

Tank Conditions for Cory Catfish

Cories need strong water flow and there should be some areas inside the tank that have high water flow. You can use air filters or air stones to create a mild water current inside your tank. Leave some areas with low water flow as it will give them a space to rest.

For substrate avoid using gravel as it can seriously injure the Catfish. The sharp edges of the gravel can cut their stomach and fins. A sand substrate is recommended as it won’t injure the Cories. Avoid using white sand because if there is any tank waste that settles on it, it can make the sand look dirty.

One important thing to note here is that It can be difficult to grow live plants in a tank with a sand substrate. Sand is not effective at absorbing nutrients that the plant needs. To take care of this you can add a root tab to your substrate.

Tank Maintenance 

The water conditions like temperature, pH level, and dissolved organic compounds should be monitored daily. Make sure the water filters are running properly and are efficient at cleaning the water. You can use a water testing kit to check the tank conditions.

The good thing with Cories is that they are scavengers and will feed on decaying plants or organic matter that will help to keep the water clean.
a close up of a cory catfish

Perform a 20% water change every week to ensure that the ammonia, nitrates and nitrite levels stay under control. Make sure you only add dechlorinated water to your tank after performing water changes. 

Best Tank Mates for Cory Catfish 

Cories are timid and will not get aggressive even if threatened. Keeping peaceful fish species is recommended as it will help to make them feel secure and keep them healthier.

A few great tank mates for Cories are:

Avoid keeping Cichlids and Barbs with Cories as they can become aggressive or nip the Cories.

Health Issues

While buying a Cory Catfish, check them carefully. A healthy fish will be active, bottom-dwelling, have undamaged fins, clear eyes and will have bright coloration on their skin.

Most diseases in fish are due to poor water quality and maintaining stable water conditions will ensure your fish is healthy.

Some common diseases in the Cories are:

Red Blotch

Red Blotch is a common disease found in the Cory Catfish. The disease results in bloody sores on their skin, especially around the belly. The sores are made of dead white skin and sometimes may even have blisters on them. Red Blotch is caused by an unidentified bacteria but it is believed to be similar to what causes fin rot, another similar disease. Poor water quality and accumulation of toxic compounds at the bottom are thought to be reasons why your fish may get this disease. Improving the water quality and giving them antibiotics will help to treat the disease.

a cory catfish in an aquarium

White Spot Disease (Ich)

Ich is one of the most common diseases found in Freshwater fish and in Cory Catfish. The disease is caused by a parasite that affects the gills and fins of the body. Poor water conditions and stress are major reasons that can lead to the fish catching this disease. When a fish becomes infected with Ich, it tends to rub against hard objects such as decorations, rocks and the substrate.

Symptoms include white spots on the body, breathing difficulty and fish rubbing against hard surfaces. In comparison to other fish diseases, these symptoms make it easy to identify if your fish is infected. 

A major concern is that this disease is highly contagious and can easily spread to other fish in your aquarium. If not treated early on, it can even cause respiratory issues. 

Treatments include slightly increasing the water temperature, adding medication to the tank and performing a large water change. If you have a community fish tank then it is suggested to move the infected fish into a quarantine tank and then treat them.

fish flakes

Feeding Cory Catfish

Like other bottom-dwelling fish, the Cory Catfish are natural scavengers. They will always look for dead plants or uneaten food on the tank bottom to eat. They should also be fed with the other fish as waste materials should not be their only source of food. Cories are omnivores and need to be fed regular fish food to keep healthy.

They can be fed algae flakes or algae wafers, pellets and bottom feeder tablets. You may feed them bloodworms as an occasional treat. If you plan to breed fish you should know that Cories tend to eat the eggs of other fish species.

They should be fed once a day and should be no more than what they can eat within 5 minutes.  

Related Questions on Cory Catfish:

Are Cory Catfish venomous?

Cories have sharp spines on their fins that do release a mildly toxic chemical when they feel stressed or threatened. The toxin is not fatal to humans. It will only produce a mild irritation or sting if the spine cuts your skin. If you have to handle the fish or move them out of the tank, you should be careful to not touch their spines. 

Because they release this chemical when they feel threatened, it is not recommended to add the bag water used to transport them. The Cory may have released the toxin into the bag water while feeling stressed inside the bag. Adding this water could cause other fish in the tank to become sick.

Is it normal for Cory Catfish to come up to the surface?

Sometimes the Cories will rise to the surface of the tank to breathe in air. Many fish do this in the wild to breathe oxygen but in captivity, it could be a result of poor water quality. For Cories this behavior is normal and does not really mean there is insufficient oxygen in the water. There should be a concern only if the behavior becomes frequent. In this case, the water conditions need to be checked and corrective measures should be taken, if required. 

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