With their whisker-like barbels, endearing short faces, and friendly personalities, it’s hard not to fall in love with the cory catfish. These freshwater fish come in a huge number of varieties, from the adorable pygmy cory to the stunning sterbai cory, and all of them can be a unique addition to your tropical aquarium.
- Cory catfish are small, freshwater catfish known for their whisker-like barbels and friendly personalities; they are great for beginners due to their hardiness and ease of care.
- Cory catfish are not herbivorous and primarily eat meat-based foods like sinking catfish pellets, shrimp pellets, and live or frozen foods.
- Common diseases that can affect cory catfish include ich and fin rot, which can be treated with temperature adjustments and proper water quality.
However, like with any fish you plan to keep in your tank, it’s important to do your research regarding cory catfish care so you can give them the best life possible.
As someone who’s owned corys for many years (and been a catfish enthusiast for even longer!), I’ll be going over everything you need to know about corydoras, including origins, water parameters, feeding, and breeding.
What Is a Cory Catfish?
Cory catfish, also known as cory cats and cory fish, are a genus of freshwater catfish. They are small bottom-dwelling fish with armored bodies, the latter of which helps protect them from predators.
Unlike most species of fish, corydoras do not have scales – they have bony plates (dermal scutes) that cover the entire length of their bodies. Corydoras also have sharp spines on their pectoral and dorsal fins. Most species possess a mild venom which they use in self-defense when they feel threatened.
Where Do Cory Catfish Come From?
Corydoras catfish originate from South America and can be found all across the continent, from the Atlantic Coast to the Andes Mountains. They inhabit shallow, slow-moving streams and rivers with sandy bottoms and plenty of hiding spaces.
Are Cory Catfish Good for Beginners?
Corydoras catfish are great fish for beginners as they are relatively hardy fish for their size and are easy to take care of. Cory fish are playful and interesting to watch, especially when you keep them in schools of at least 6.
Did you know that there are over 160 types of cory catfish?
Many types of catfish are mildly venomous, and they can even self-poison in life-threatening or frightening situations. This is done by producing a poisonous mucus from the gills, causing all surrounding fish to die.
However, self-poisoning often kills the corydora as the process is extremely stressful.
How Big Do Cory Catfish Get?
Corydoras range in size depending on the species, but they are all relatively small. The smallest type of cory is the pygmy cory, which is a tiny 1.2 inches. The largest is the banded cory, which reaches around 4 inches in length.
How to Tell Cory Catfish Gender
Corydoras can be difficult sex as females and males look almost identical, especially as juveniles. It is easier once the fish is mature or an adult as females tend to be larger and much rounder around the belly when viewed from above.
Males normally possess a bigger dorsal fin and pointier anal fin than females.
Cory Catfish Varieties
There are well over 100 varieties of cory catfish, all of which look quite different from one another, at least in terms of color and size. Below are some of the most popular cory catfish you’ll find in pet stores across the globe.
Panda Cory Catfish
Panda corys (corydoras panda) get their name due to their striking black and off-white coloration that resembles a panda. They reach around 2 inches in length, making them one of the smaller cory species.
Personally, the panda cory is my favorite out of all the cory species because of their striking pattern!
Pygmy Cory Catfish
Pygmy corys (corydoras pygmaeus) are the smallest type of corydora, reaching a minute 1.2 inches in length. They are a silvery-gray color with a black stripe that runs along the side of their body.
Blue Cory Catfish
Reaching approximately 2.7 inches in length, blue corydoras (corydoras nattereri) are a light yellow color with green highlights around the gill plates, as well a dark bluish stripe along the middle.
Peppered Cory Catfish
Like their name suggests, peppered cory catfish (corydoras paleatus) are an olive-brown color with a series of dark-green or black patterns over their body, kind of like they’ve been sprinkled in pepper. Peppered cory catfish normally get to roughly 2.5 inches in size.
Bronze Cory Catfish
The bronze cory catfish (corydoras aeneus) has a yellow or pink body, white belly, and blue-gray pattern across their backs. They grow to about 2.5 inches and feature an orange-brown splodge on their heads.
Albino Cory Catfish
As you’ve probably already guessed by their name, the albino cory catfish is a stunning yellowy-white color with pink eyes. These albino animals are a variation of the bronze cory, and can look particularly striking in densely planted aquariums as they’re pretty hard to miss!
Emerald Cory Catfish
Emerald corydoras (corydoras splendens) are one of the larger species in the family, getting to around 3 inches in length. Their color can look either blue-green, blue, or metallic green depending on the angle of lighting.
Julii Cory Catfish
The julii cory (corydoras julii) is one of the most unique-looking corydora species due to its spotted appearance. They have a whitish-gray body color adorned with fine black spots, and reach just over 2 inches in size.
Sterbai Cory Catfish
Last but not least is the sterbai cory catfish (corydoras sterbai), which boasts a dark body, yellow belly, and white dots that cover the entirety of the fish. They get to roughly 2.5 inches in length, and can also be found in both black and albino forms.
Cory Temperament and Tankmates
Corydoras are well-known in the aquarist community for being highly peaceful, docile fish – they can be housed with pretty much all other tropical fish species provided there is another space in the aquarium.
In this section of the article, I’ll be going over the cory temperament and suitable tankmates, so make sure you stick around!
Are Cory Catfish Aggressive?
Cory catfish are the complete opposite of aggressive – they are gentle, passive, and timid creatures, just like the twig catfish, that make excellent tankmates for invertebrates and other peaceful fish.
How Many Cory Catfish Should Be Kept Together?
Corydoras are social animals, so they enjoy the company of their own kind. This bottom dweller should be kept in schools of at least 6 in order to thrive and feel safe. Corydoras are naturally timid, even more so when they are housed in insufficient numbers.
They can be housed with other species of cory like albino corys, bronze corys, etc, or the same species.
Can I Put a Cory Catfish With a Betta Fish?
Yes, corydoras can be housed with a betta fish as long as there is plenty of room in the tank for both animals. In fact, corys are one of the few species that can live with bettas due to their passive nature.
They also spend the majority of their time at the bottom of the tank, whereas bettas primarily live near the water surface, so both species will rarely bump into one another.
Do Corydoras Clean the Tank?
Corys can help keep the aquarium clean by eating leftover food from other fish that has sunk to the substrate. However, you’ll need to perform regular water changes and tank maintenance to keep your aquarium and its inhabitants healthy.
What Fish Can Live with Corydoras?
Corydoras get along well with other fish and can live with practically any passive species due to their peaceful temperament, but some good tank mates for these catfish include:
- Betta fish
- Columbian Shark
- Endler’s livebearers
- Freshwater angelfish
- Gouramis: Dwarf, Honey
- Other Catfish: Bumble bee catfish, Glass catfish, Otocinclus catfish
- Other corys like the albino cory catfish, julii cory catfish, and corydoras panda
- Shrimps: Amano, Cherry, Filter
- Snails: Mystery, Japanese trapdoor snails, Nerite, and Ramshorn
- Tetras: Black Phantom Tetra, Black Skirt, Ember, Neon, Ruby Tetras, Rummy-nose tetras
- Yoyo Loach
- Zebra danios
Cory Tank Requirements
What Size Tank Do Cory Catfish Need?
The minimum tank size for corydoras depends on the variety and number of fish you want to own. These fish range from 1.2 inches to 4.5 inches in length, so smaller species like the pygmy corydora won’t need as much space as larger varieties like the banded cory.
For cory cats less than 2 inches in size such as the pygmy cory catfish and panda cory, a 10-gallon aquarium is adequate for a group of between 6 to 8. For larger corydoras like the albino cory catfish and peppered cory, at least 20 gallons (ideally, 30 gallons) should be suitable for a group of around 6.
Corydoras spend most of their time at the bottom of the tank, so it’s best to use a long tank rather than aquariums that are tall, hexagonal, circular, etc. These fish love to scavenge and prefer larger floor space over swimming space.
Cory fish originate from warm waters, so they require a tropical freshwater aquarium. The ideal water temperature for these fish is between 74° and 80° F. If you live in a cool climate, you’ll need to make sure you install a good-quality aquarium heater in your cory catfish tank to keep the water at a consistent heat.
The best pH for a captive-bred cory cat is between 7.0 and 8.0, though wild-caught corydoras may need a slightly lower pH level that’s between 5.5 to 7.0.
The ideal water hardness for corydoras is between 5 to 19 dGH. You can check both the pH and water hardness levels of your tap water using aquarium testing strips or solutions.
How Many Cory Catfish In a 10-Gallon Tank?
The number of corydoras catfish you can house in a 10-gallon tank depends on the variety and whether you plan on keeping any other fish. For armored catfish under 2 inches in length like pygmy and panda corys, between 5 to 8 should be sufficient with good tank maintenance.
Larger species like corydoras aeneus (bronze cory) and albino corydoras, between 2 to 4 is preferable. However, as mentioned earlier, corydoras are social fish and thrive when kept in schools of at least 6.
If you’d like to keep corydoras with the same species or other fish like, you’ll need an even bigger tank. Most aquarists use the “1 gallon per 1 inch of fish” to calculate the number of fish they can house in their tank.
What Do Cory Catfish Eat?
Contrary to popular belief, corydoras catfish are not herbivorous – they’re mostly carnivorous! This means they primarily eat meat-based foods, but they will occasionally feed on plant matter. Unlike some catfish like the clown pleco and chocolate doradid, corydoras aren’t algae eaters.
They might nibble on some algae wafers if you house them with herbivorous tank mates, but don’t expect them to scrape algae from the tank walls, decorations, substrate, etc.
What to Feed Cory Catfish
Although corydoras catfish are scavengers and will happily eat leftover food from other fish in your tank, you’ll still need to supplement their diet to ensure they get the right nutrients.
As cory fish spend most of their time near the substrate and they are bottom feeders, it’s best to use sinking catfish pellets, shrimp pellets, or bottom feeder tablets. You can also feed them live, freeze-dried, and frozen foods like bloodworms, brine shrimp, and black worms.
My albino cory catfish particularly loves Repashy gel foods (normally used for reptiles) as a treat!
When to Feed Cory Catfish
Corydora catfish should be fed once or twice a day. Either in the morning or evening is fine, but these fish tend to be most active during the day.
How Much to Feed Cory Catfish
You should feed cory catfish as much food as they can eat within 2 to 3 minutes. After this time, remove any leftover food with a fish net.
How Long Can Cory Catfish Go Without Food?
A healthy cory catfish can safely go without food for up to 7 days. However, if you’re unable to take care of your fish for a few days, I’d suggest asking a friend or family member to check on your tank and feed its inhabitants just to be on the safe side.
Cory Health Issues – Common Diseases
Ich (White Spot Disease)
Ich is one of the most common diseases that can affect aquarium fish. It’s easy to tell if your corydoras have ich as small white spots will appear on their body, kind of like they’ve been sprinkled with salt. Sufferers may also be lethargic and lose their appetite.
Ich can be prevented by good tank maintenance and quarantining new fish for a period of at least 2 weeks.
Unfortunately, ich can be fatal if left untreated, especially if the affected fish is already weak.
Gradually increasing the tank temperature to 80° F can help kill ich, as can medications containing formaldehyde, malachite green, or copper sulfate.
Fin rot is another common disease that can wreak havoc on aquarium fish. It’s normally caused by poor water quality, nitrate buildup, and a general lack of tank maintenance. This disease will cause your cory’s fins to tear, fray, and blacken at the edges.
In extreme cases, the entire fins may completely erode away. The best cure for fin rot is improving the quality of the water by regular water changes to ensure consistent water parameters.
Aquarium antibiotics and adding Indian almond leaves to the tank can also help your fish fight the infection.
How Long Do Cory Catfish Live?
With good care, catfish corydoras have a lifespan of around 5 to 8 years.
Why Is My Cory Not Moving?
There could be a few reasons why your cory is not moving, but usually it’s due to exhaustion. They could be sleeping or being bullied by other tank mates in your aquarium.
The latter is especially true if you keep your corydoras with larger, aggressive fish. Another reason why your cory could be inactive is due to injury or illness. Check your fish over for symptoms like inflamed gills, cuts/wounds, lesions, rapid breathing, torn fins, etc.
If you notice the aforementioned signs, it’s a good idea to contact a veterinarian that specializes in aquatic life or seek advice from aquarium professionals, such as your local fish store.
Lastly, if your catfish corydoras is completely unresponsive and shows no signs of life, then they may have passed away.
Can You Breed Cory Catfish?
Yes, you can breed cory catfish in captivity! In fact, they’re one of the easiest freshwater small fish to breed. Most cory catfish become sexually mature at around 6 to 9 months old, so after this time, they will be ready to mate.
How to Breed Cory Catfish
Armored catfish will readily breed without intervention, but there are a few things you can do to increase your chances of success.
Step 1: Select a healthy male and female cory catfish, then place them in a separate tank with sandy substrate and plenty of hiding places. This will replicate a natural habitat for the fish.
Step 2. Feed the pair nutritious live food like small insects and worms such as bloodworms, brine shrimp, and blackworms.
Step 3: Over the course of a few days, reduce the water temperature of the breeding tank until it is around 3 degrees colder than the main tank. This will help induce spawning.
Step 4: If the pair are interested in mating, the female will look a lot rounder than usual as she will be carrying eggs.
Step 5: During spawning, the female cory will approach the male’s abdomen to encourage him to release sperm and fertilize the eggs. The female will then lay the eggs in her pelvic fin, then release the eggs onto the sand substrate.
Step 6: Once the female has deposited all the eggs, move the parents to the main tank so they don’t eat the little guys. Perform partial water changes on the breeding tank at least 3 times a day so the eggs don’t grow fungus.
Step 7: After almost a week, the eggs should hatch. Once the fry start swimming, you can feed them baby brine shrimp. When they are a few weeks old, you can move them to a new tank.
What Do Cory Catfish Eggs Look Like?
Cory catfish eggs are white and around 1mm to 2mm in size. They are usually laid in small clutches of 10 to 20 eggs.
If the eggs are successfully fertilized, they will turn a beige color with tiny black spots in the middle.
How Many Eggs Do Cory Catfish Lay?
The number of eggs corydoras lay varies per species, but it can be anywhere from 20 to 100 eggs at a time.
Did you know that corydoras usually spawn every week once they are sexually mature?
How to Tell If Cory Catfish Eggs Are Fertilized?
Fertilized cory eggs will be a beige color and will develop a dark spot in the middle once they are close to hatching. Infertile eggs, on the other hand, are white or transparent.
How Long Does It Take Cory Catfish Eggs to Hatch?
It takes around 6 days for cory catfish eggs to hatch.
Is the Cory Catfish For You?
If you’re looking for a hardy fish that’s peaceful, friendly, and entertaining to watch, you can’t go wrong with the cory catfish.
This bottom dweller is easy to care for and makes an excellent addition to a community tank with other passive fish.
Better yet, they help keep your tank clean by munching on leftover food from other inhabitants, which saves you a bit of time and work!
It’s no wonder why the corydoras catfish is one of the most popular freshwater fish in the aquarist community due to their gentle nature, interesting behavior, and simple care. I hope this article helped you learn a little more about these tiny catfish and, hopefully, encouraged you to add a school to your tank!
They’re one of my favorite freshwater fish – in fact, most of my tanks have several species of cory catfish swimming about in them, including corydoras pygmaeus, albino cory fish, and panda corydoras.
If you enjoyed this article, be sure to share with your friends and family so they can learn a new thing or two about corydoras!