The Cory catfish is one of our most recommended freshwater fishes for aquarists of all experience levels.
They look fantastic, they’re easy to care for, and they are super friendly. There really isn’t anything not to love about this fish!
This care guide will give you a complete understanding of Corydoras and what needs to be done to help them live a long and happy life.
We hope you enjoy it!
Table of Contents
- Species Summary
- Appearance And Size
- Types Of Cory Catfish
- Cory Catfish Care
- Recommended Tank And Water Conditions
- Food & Diet
- Typical Behavior & Temperament
- Good Tank Mates
- Bad Tank Mates
- Breeding Cory Catfish
- The Wrap Up
A classic addition to any freshwater aquarium, the Cory catfish is widely popular among aquarists ranging from beginner to experienced. Like most catfish, these guys are bottom dwellers that want to do their thing without disrupting others.
Also known as Cory cats, armored catfish, Corydoras catfish, and Cory fish, these peaceful creatures make up the entire genus Corydoras, which includes more than 165 named species.
These fish are native to South America and regions east of the Andes Mountains extending all the way to the Atlantic Ocean. The genus name is derived from the Greek words kory, or helmet, and doras, or skin, which appropriately describe two of the fish’s most distinctive characteristics.
Appearance And Size
Varying according to species, the average Cory catfish size generally ranges in length from about 1 inch to over 4 inches, although older females will regularly exceed 3 inches in length.
As befits its scientific name, The Cory is protected with an armor consisting of bony plates that run along the length of its body. The fish’s flat underside is well adapted to life at the lowest levels of the water.
Their horizontal pectoral fins allow them to comfortably rest on the substrate. Sail-like in appearance, the fish’s vertical dorsal fin is generally pointed; however, it may be round in some species. The Cory’s tail fin varies in length and height among species but is usually forked no matter the type.
The fish’s short face features ringed wide, lovable eyes. Also located on the face, three pairs of barbels that resemble whiskers help them find food in the substrate.
Coloration varies among species of Corydoras, ranging from pale or albino to iridescent, although many are in shades of brown that help camouflage them in the substrate.
Types Of Cory Catfish
There are many different types of Cory catfish out there, so having some basic knowledge about each of them (and what they look like) will help you in the buying process.
Albino Cory Catfish
Albino Cory catfish have an interesting look that some tank owners want. They have the classic red eyes that you find in albino animals and their bodies are a light white/pink combo.
Unlike a lot of the other types on our list, Albino Corydoras can only be purchased from specific breeders due to the fact that they don’t come from the wild. They tend to be a little smaller than average but only slightly.
Green Cory Catfish
Green Cory catfish are very popular in the aquarist community. This is partly due to the neat looking green accents that you can see on their sides, and their passive nature. While all types of these fish are very peaceful, Green Cory catfish take it to another level. They’re about as timid as it gets!
Panda Cory Catfish
This is another kind that gets a lot of attention. The Panda Cory catfish gets its name because of the white primary coloring on their body (this can be orange sometimes) and the black around their eyes. This gives them a unique look that resembles a panda bear.
Peppered Cory Catfish
Peppered Cory catfish are extremely popular and are what a lot of people are referring to when they talk about this species. Another name for this is the “spotted Cory catfish” so if you hear that used, this is the type that is being talked about.
The main coloring that is found on the peppered Cory is brown (ish) with some darker spots scattered all over their body.
Pygmy Cory Catfish
The name says it all with the pygmy Cory catfish (Corydoras pygmaeus). These little guys are typically only an inch in length on average.
Because of this, you will want to take extra care to make sure they are safe in your tank and aren’t paired with any other fish that can cause them harm. They will get stressed easier than other Corydoras, so you want to make sure they feel completely comfortable.
Julii Cory Catfish
This is another small type that is not commonly found in aquarium stores or even with Cory breeders. They have a very spotty pattern all over their bodies and are known for their expressive eyes.
Emerald Cory Catfish
This is one of our favorite types without a doubt. They have a very sharp and colorful green tone to their bodies that really light up in certain angles underwater. If you want a fish that will really add a splash of color to your tank, you can’t go wrong with the Emerald Cory catfish.
Cory Catfish Care
Corydoras are pleasant and hardy fish that are very easy to care for. If you’re someone who likes a low-stress and aquarium experience, this is a great fish for you.
Be aware, however, that it’s possible to lose a Cory shortly after it comes home from a store tank. Stress during transport and the difference in conditions between tank waters can, unfortunately, prove fatal to catfish.
For this reason, be extra careful when bringing them home. Also, make sure the tank water conditions at home are similar to those they’re used to.
One of the best ways to keep your Corys healthy is to maintain stable tank conditions. Partially change the water weekly to prevent nitrate buildup, which even in small amounts can make the fish more susceptible to disease, especially barbel infections.
Quick Tip: When cleaning the tank or rearranging decorations, keep the stirring of the substrate to a minimum, as the decaying matter will pollute the water and release bacteria. Excessively stirring the substrate can also cause an increase in ammonia. In addition, make sure any new water you add to the tank is dechlorinated.
Aside from being harmful to the Cory itself, a stressed catfish can actually release toxins that are harmful to other fish in your tank, potentially even killing them.
Because these fish are very social, it’s best they can interact with their own species. Four, five or preferably six or more fish will happily school together and often swim in unison. A happy fish is a healthy fish, and you’ll be happier too as you watch their water ballet moves!
As is common with other species of fish, Cory catfish can become infected with Ich, or white spot disease. This is one of the most common diseases in fish and can damage the gills and skin, threatening the fish’s respiratory system and potentially resulting in death.
The best way to avoid Ich is through prevention by quarantining new fish and aquarium plants before adding them to your tank. It goes without saying that washing your hands before and after working with each tank and using separate equipment for each will also minimize the possibility of infection.
Easy to care for, the good-natured, hardy Cory catfish has a lifespan can live between five and seven years in the wild but can live more than 20 years in captivity under ideal conditions.
This means if you provide the proper care and do what it takes to ensure that they thrive, they should be with you for a while!
Recommended Tank And Water Conditions
Like any fish, Corydoras will thrive if they are placed in the proper tank and water conditions. Although they are hardy fish that don’t require a significant amount of special care, there are some basics that you need to be aware of.
Because there are so many species of Cory catfish, the size of the tank you need will vary accordingly. A 10-gallon tank is the bare minimum but you will need to go larger, preferably 20 or 30, if you keep several species.
If you’re a beginning aquarist we recommend at least a 20 gallon tank if you have a school of five or more fish. As you add more fish to your tank, you’ll need an additional 2 to 4 gallons per fish.
A typical tropical fish, the Corydoras needs consistent water parameters that mimic their natural environment. Significant deviations from this range can result in stress and health issues.
- Water Temperature: Between 70°F-80°F
- pH Levels: 6.0-8.0 (this can vary based on the
- Alkalinity Levels: 3-10 dKH
Note: The pH requirement may vary, however, as fish bred in captivity need a level between 7.0 and 7.8, while Corydoras bred in the wild may require a lower pH between 5.5 and 7.0.
Be sure to frequently test the water for nitrate levels. Partial water changes should help keep nitrate low. Ammonia and nitrite are extremely dangerous to fish and even in small amounts can prove fatal to Cory catfish. Always keep these levels at 0 ppm.
Additional Tank Suggestions
Cory catfish spend most of their time at the very lowest levels of the water, so keep at least 2 inches of substrate on the bottom of the tank. Soft sand is by far your best choice, as the jagged edges on gravel or rock can damage the fish’s fins, barbels, and underside.
Also make sure to provide them with a shady hiding spot, such as driftwood or caves.
Mimic the Cory’s natural habitat of slow-moving, shallow streams and inlets with a weak filter setting and plenty of plants, including Java fern, crypts, hornwort, pennywort, Java moss, dwarf hairgrass or Amazon sword.
The plants also provide an area shaded from the light, much as do trees in the fish’s native habitat. However, they also love high water flow where they can dance along with others of their species in the higher levels of the tank.
Although Corys are very adaptable to any type of lighting, they do prefer the lower-light environment of their natural waters. Your plants, however, require sufficient lighting. LED lighting is an excellent choice for both, as it lasts much longer and is cooler than traditional lighting.
Lastly, be sure your tank is covered because these fish have a habit of jumping to the surface for a bite of food or a gulp of air. With the aid of their special intestinal lining, Cory catfish actually adapted the behavior of breathing oxygen from the atmosphere in order to survive in waters that contain low oxygen levels. This instinctive behavior remains even in water where the oxygen is sufficient.
Food & Diet
In their native habitat, Cory catfish scavenge the substrate for worms, larvae and small insects. They will dig into the substrate with their mouths and sucks up the food, often digging so deep that much of their face can actually be covered! They will also gladly eat vegetable matter that falls into the water.
In captivity, sinking pellets are the best Cory catfish food to mimic their natural wild diet and allow them to be scavengers. Bottom feeder tablets, shrimp pellets, and algae wafers are also good choices, although being omnivorous means they will accept flakes, as well.
Daphnia and bloodworms are excellent treats. Try to occasionally vary the food you give these fish so they can get all the nutrients they need.
Feed your fish once a day but only as much as they can consume within 5 minutes, then quickly remove the leftovers. Also, be aware that Corydoras will occasionally eat small eggs of other fish species!
Typical Behavior & Temperament
Cory catfish are famous for their sweet temperament, which is one of the top reasons they’re so popular with aquarists. They spend the majority of their time minding their own business at the bottom of the tank, peacefully scavenging for food or resting.
Although a Cory can survive alone, it’ll be a lot happier if it can interact with others of its own kind. These fish will often feed together, but resting time is when they’re most likely to remain close.
Having multiple Corydoras in your tank also makes them much more fun to watch! When they’re schooling in groups of five or more, they’ll provide you with a synchronized water dance that is truly fascinating.
Overall these are about the least aggressive fish you can find. They won’t attack others and will hide without defending themselves against their attackers.
Good Tank Mates
The ideal Cory catfish tank mates are other Corys, even those of other species, as they’ll gladly school in groups of five or six. They’ve even been known to school with other shy fish of similar colors, such as tetras, a practice that’s common in the wild.
Other peaceful fish that will get along with Corydoras include colorful, live-bearing fish, such as guppies, platies, swordtails, and mollies. In addition, other types of aquarium catfish, including Otocinclus and plecos, will peacefully get along with your fish, as will fan and filter shrimp and freshwater snails.
Bad Tank Mates
Never keep Corys in a tank with aggressive fish. Some common fish to avoid that fall into this category are:
- Cichlids (African and Jack Dempseys being two popular varieties)
One common question that a lot of beginners have is if they can pair a Cory with a betta fish. This is possible if your betta is peaceful (you should still be cautious though), but if it’s aggressive then it’s something you should avoid completely.
Aggressive fish can attack, injure or even kill Cory catfish. In summary, the best possible scenario will still result in your poor fish being under a tremendous amount of stress.
Another no-no is the aquarium crayfish. Their claws can make quick work of your Cory.
Breeding Cory Catfish
Breeding Cory catfish is relatively easy, provided you set up a tank strategy that helps the fish feel comfortable and secure enough to spawn. There are two basic approaches that you can choose: the dedicated breeding tank and the dedicated fry tank.
Option 1: Dedicated Breeding Tank
The dedicated breeding tank method involves setting up a separate tank specifically for breeding. This tank is usually bare with little or no substrate, so it’s very easy to clean. You place the breeding group in this tank until they’ve spawned; and when they’re done, return the adults back to the main tank and leave the fry in the breeding tank where they’re more likely to survive.
Option 2: Dedicated Fry Tank
With the dedicated fry tank method, the fish spawn in the main tank. You then transfer the eggs to the fry tank where they hatch and grow. This approach is easier for you and less stressful on the adult fish; however, the fry may not have as good a chance of survival as they would with the dedicated breeding tank method.
To induce spawning, feed your Corydoras several small meals a day with a high-protein diet consisting of both live or frozen foods and quality prepared flakes or pellets. After a week or two, your females should “show” they’re carrying eggs.
You might get lucky with Corys who eagerly spawn without your help. If not, replace about 25 to 50 percent of the water with that about 2 to 3 degrees cooler, which simulates the cool summer rainfall when they naturally breed in the wild. However, never allow the water temperature to drop below 65 degrees.
Be patient. Even if your Corys don’t spawn in one day, they will within a few. Most of the time, they’ll lay their eggs on the tank wall but will sometimes choose plants, decorations, the filter or even snails!
The eggs should hatch between three and six days. The fry won’t need your feeding for a few days, as their bodies naturally absorb nutrients from the attached egg sack.
The Wrap Up
As you can see, there are very little downsides to owning a Cory catfish. They will spruce up the look and feel of your tank with their vibrant colors and get along with the other community fish in your tank.
They’re also super easy to take care of, which is a big plus in our book. Sometimes more difficult fish can be rewarding, but that experience isn’t for everyone.
We’re huge fans of this fish and we highly encourage you to give them a chance. We think you’ll be very happy with them!