Cory Catfish And Bettas: Are They Good Tank Mates? Our Guide

Bettas are flashy fish known for their aggressive behavior. But, with the ideal tank mates, betta fish can thrive in community tanks.

Finding suitable tank mates for a betta is no easy task. Betta tank mates must have a docile temperament.

Corydoras catfish seem like a good option because of their peaceful nature.

So, can cory catfish and bettas live together in the same tank?

Corydoras catfish make perfect tank companions for betta fish in the right conditions. The calm temperament of corydoras balances the aggressive behavior of a betta fish. Providing plenty of tank space and hiding spaces ensures a successful pairing.

Tank Size and Space Considerations: Bigger Is Better

Corydoras catfish swim in schools and thrive in groups of six or more. A larger group gives corys a sense of security.

Schooling fish need extra space in the tank for swimming. Corys rarely stray from the group, even when they eat and rest.

The ideal tank size needed for corys and a betta fish is 20 gallons.

A 20-gallon tank provides enough space for corys and bettas along with lots of plants and hiding spots.

If you plan on adding more than six corys, a 30-gallon tank is better.

Smaller tanks create overcrowded conditions, increasing the risk of aggressive behavior.

Larger tanks also help maintain stable water parameters.

Filling the aquarium with plants creates a natural environment for your fish. Big-leaved plants serve as hiding and resting places.

You may use silk plants as an alternative to live aquatic plants.

Avoid artificial plants with plastic leaves. Plastic plants have sharp edges and may tear a betta’s delicate fins.

Other decorative hiding spots include small caves and pieces of driftwood.

Many hiding spots provide your fish with places to explore and escape from each other.

Place a gravel substrate around three inches deep in the bottom of the tank. This depth is necessary for supporting aquatic plant roots.

Do Corys and Bettas Share the Same Water Parameters?

The table below shows the ideal water parameters for cory catfish and bettas.

There is enough overlap in the water parameters of corys and bettas for both fish to have a comfortable environment.

A water temperature of 78° degrees Fahrenheit (26° C) works well for both species. The ideal water pH is 7.0, which is neutral.

Stable water parameters are vital for the health of your fish.

Sudden fluctuations in temperature cause temperature shock and other illnesses.

You must also test for toxins such as ammonia, nitrites, and nitrates.

Levels above 0 ppm of ammonia or nitrites are harmful to fish.

Nitrates are less toxic than nitrites, and acceptable nitrate levels are less than 40 ppm.

Aquarium test kits tell you everything you need to know about your tank water. Use them often and ensure the parameters are within the acceptable range.

Weekly partial water changes help keep these water parameters in check.

Only remove 20-25 percent of the tank water during a weekly water change. Removing more water than this upsets the balance of your nitrogen cycle.

Corydoras catfish come from harder water than bettas. But years of captive breeding mean they tolerate a water hardness of 3-4 dGH as well.

Water hardness is not much of a concern as long as you maintain ideal temperature and pH levels.

The Best Diet and How To Feed Them

Cory catfish are omnivores, while betta fish are strict carnivores.

Since corys are bottom feeders, a high-quality sinking wafer is the best staple food option. They also scavenge the substrate for food leftovers and algae.

As carnivores, betta fish need a high-protein diet of meat-based foods. Their staple diet consists of a protein-rich pellet food.

Both fish species enjoy a varied diet. You may include treats of live, freeze-dried, or frozen foods 2-3 times per week.

Some excellent treat options include:

• Bloodworms
• Tubifex worms
• Baby brine shrimp
• Daphnia
• Mosquito larvae

Betta fish need a day of fasting every week.

Fasting allows for the proper digestion of residual food in the stomach. It also prevents issues like bloating and constipation.

Corydoras can use the fasting days to engage in their natural foraging behavior. They are happy digging through the substrate for tasty morsels from betta food.

Feed your corys and betta fish two small meals daily for the other six days of the week.

Place betta pellets in the tank first, then drop in the sinking wafers for your corys. This keeps the betta distracted near the surface while the corys eat.

Do not feed your fish more than they can eat within 2-3 minutes. Overfeeding causes health issues in your fish and disturbs your water parameters.

Remove leftover food when feeding time is over. This prevents ammonia and nitrite spikes.

Peaceful Coexistence or a Fight Waiting To Happen?

Most fish keepers keep bettas alone in a tank because of their aggressive temperament. There is no such thing as a lonely betta fish, and they do not mind their solitary existence.

Corydoras catfish are a peaceful fish species with no interest in fighting.

With their different personalities, you may wonder if corys and bettas can ever get along.

The short answer is yes, corydoras catfish and bettas get along well once they adjust to their new living conditions.

Compatibility between corys and a betta largely depends on your betta’s personality.

An aggressive betta is not a good candidate for a community tank. A betta with a more timid personality is a better choice.

Your tank setup also plays a role in preventing aggression among your fish.

A large tank filled with many plants gives your fish enough space for swimming and exploring.

Floating plants like frogbit and hornwort provide extra cover and security for the fish.

A tank divider allows both fish species to establish their own territory. Transparent tank dividers let the fish see each other without worrying about fighting or aggression.

Once the fish get used to each other, you may remove the divider and allow for more interaction.

You need a new tank for your corys and betta fish as well. Placing corydoras in an established betta tank is a bad idea.

When a betta sees an entire tank as its territory, any new fish are considered a threat.

Corys and bettas need a proper introduction for a successful community tank.

How To Create the Best Tank Setup and Habitat

Once you choose your tank, you must consider what goes inside of it.

Filling the tank with water and adding your fish is not enough.

Several things must take place for the health and comfort of your fish.

Learn more about choosing the best tank components with our article on how to set up a betta tank.

Install an Aquarium Heater

Invest in a quality aquarium heater and thermometer.

Many tank heaters have built-in thermostats, but sometimes they malfunction.

A separate thermometer lets you know the heater works correctly.

Install a Quality Filtration System

Corys and bettas also need a filter with a low flow rating.

Neither of these fish species swims well in strong currents.

A filter with a slow current prevents toxins and bacteria buildup without stressing your fish.

Add Tank Lighting

Adjustable LED lighting is crucial for your tank, especially if you have a lot of plants.

Corys and bettas need periods of light and dark to regulate their eating and sleeping habits.

Both of these fish are sensitive to bright light. An adjustable light lets you control the brightness to the right level for your corys and bettas.

Do Not Create Artificial Territories

All of your fish must have full access to the entire tank. Aside from a tank divider, do not attempt to create separate territories for your corys or bettas.

Once your fish have acclimated to the new tank and each other, they will naturally establish their own territories.

Establish a Nitrogen Cycle

The most important part of your tank setup is the nitrogen cycle.

It takes up to eight weeks for a complete nitrogen cycle. The nitrogen cycle establishes good bacteria in the tank.

This bacteria works with your tank’s filter and converts ammonia to nitrites. Nitrites then convert to less-harmful nitrates.

Your tank must be fully cycled before adding your fish. Sudden fluctuations in water parameters are dangerous and cause health problems in fish.

Tips on Choosing Tank Decor

Another component of a good tank setup is the decor.

Any type of tank decor you choose must have rounded edges.

Bettas have delicate fins, which may get snagged on sharp edges or coarse surfaces.

Substrate

Substrate options for your community tank include fine sand or smooth gravel.

Sand is better for the bottom-feeding corydoras, but gravel is better for anchoring plants.

Gravel may be your best option if you have a heavily planted tank.

Corys use their downturned mouths and barbicels for digging in the substrate. Choose smooth gravel, as corys are prone to injuries from sharper rocks.

Aquatic Plants

Include a variety of plants in your tank setup.

Some excellent plant options are:

• Java moss
• Amazonian frogbit
• Amazon swords
• Java fern
• Anubias

Plants create a more natural environment and offer additional hiding places for your fish.

Hiding Places

Hiding places are vital to a successful community tank with corys and bettas.

The muted colors of corydoras catfish are less likely to attract a betta’s attention. Still, these small fish need hiding places where they feel more secure.

Likewise, your betta needs a place to relax away from the corys.

Small caves, pieces of driftwood, and smooth rocks make excellent hiding spots.

Health Issues in Corys and Bettas: How To Prevent Them

There are several common health issues found in both corydoras catfish and betta fish, such as:

• Ich
• Fin rot
• Pop eye
• Dropsy
• Swim bladder disorder
• Gill flukes

There is also an illness called red blotch disease, which mainly affects bottom dwellers like corydoras catfish. This disease causes red patches on the underside of corys.

Symptoms vary according to the type and severity of the disease.

General signs of illness include:

• Lethargy
• Loss of appetite
• Erratic swimming pattern
• Not moving

For a full list of symptoms and treatment options, read our article on common betta diseases.

The same symptoms apply to corys as well.

If you suspect one of your fish is sick, move them to a separate quarantine tank right away. Removing the sick fish prevents the illness from spreading to others.

Most treatments must be done in the quarantine tank. Several medications have long-term effects on a tank’s water parameters.

Causes of Illness in Corys and Bettas

The most common causes of fish diseases are poor water quality and an unhealthy diet.

Corys and bettas are sensitive to ammonia and nitrite poisoning.

Poor tank maintenance and cleaning habits increase the risk of ammonia and nitrite spikes.

Prevent these toxins from building up by performing partial water changes every week.

Remove 20-25 percent of the water from the tank and gently clean the substrate with the gravel vacuum. Take care not to disturb the fish too much when cleaning.

Add a water conditioner to the new water before pouring it into the tank. The water conditioner removes harmful chlorine from tap water.

An unhealthy diet also contributes to fish diseases.

Without proper nutrition, your fish’s immune system weakens. This makes your fish prone to illness from bacteria and parasites.

Parasites are sometimes introduced to the tank through live food. Buying live food from reputable sources lowers the risk of parasites.

Preventing Illness in Corys and Bettas

Keeping your tank clean and your water parameters in the correct range prevents a lot of common illnesses in fish.

Always feed your corys and bettas a nutritious diet. Ensuring your fish get essential nutrients helps boost their immune system.

Many times, diseases come from new fish that are already sick.

Avoid buying fish with swollen bellies, body lesions, or ragged fins. These are all signs of poor health.

Quarantine new fish for 4-6 weeks before adding them to the tank. Watch their behavior for any signs of illness.

Healthy corydoras catfish, and bettas are active swimmers with a good appetite.

If your fish are hiding a lot or refusing to eat, this may be a sign of stress from the new environment.

When this behavior continues for more than a few days, it signifies something more serious.

Top 4 Tips for Successfully Acclimating Corys and Bettas

A stressful introduction of your corys and betta fish increases the risk of aggressive behavior.

Avoid giving your community tank a bad start by properly introducing and acclimating your fish.

Prepare the Tank

Ensure your tank is fully cycled and water conditions are optimal before adding the fish.

Check the tank temperature, pH, and ammonia levels. If anything is out of range, correct the issue.

Add the Cory Catfish First

Place the cory catfish in the tank before adding the betta fish. This lets the corys explore and find hiding places without feeling threatened.

Avoid temperature shock by floating the container of corys in the tank water. Their bodies need several minutes to adjust to the tank temperature.

Since cory catfish are bottom dwellers, they will likely settle near the substrate.

Give the corys a couple of hours alone in the tank.

Add Your Betta Fish

Once your corydoras catfish are settled, you may add the betta fish.

Float the betta container like you did with the corys to prevent temperature shock.

Betta fish have a labyrinth organ, which allows them to breathe air. They also have upturned mouths for eating food at the surface.

For these reasons, your betta will swim in the middle or upper parts of the tank. This gives it easy access to breathe air and grab food.

Watch Your Fish

When all the fish are in the tank, watch their behavior for signs of aggression.

If your betta seems too aggressive with the corys, consider adding a tank divider.

Once your betta calms down after a day or two, remove the tank divider.

Keep watching for bullying or aggressive behavior.

If your betta attacks the corys, you must remove it from the tank. Have a separate tank handy in case the pairing does not work out.

In most cases, the betta is not bothered by the corys.

They are easy enough for your betta to avoid since they stay near the bottom of the tank. The corys also do not pose a threat to your betta because of their docile nature.

What About Other Tank Mates?

You may add other tank mates to your cory-betta tank as long as there is enough space. The new tank mates must also have a friendly temperament.

Avoid brightly-colored fish your betta might attack.

Some good tank mate options for a cory-betta tank are:

• Neon tetras
• Nerite snails
• Harlequin rasbora
• Otocinclus catfish
• Kuhli loach

These species do well in the same tank parameters as corys and bettas.

Do not add too many new fish at one time. Follow the same protocols for quarantining as well.

Slowly introduce the new tank mates as you did with the corys and betta.

Watch for aggressive behavior, and remove the new fish if things don’t work out.

FAQs About Keeping Cory Catfish with Bettas

Cory Catfish and Bettas: Avoiding Cat-Astrophe

A community tank with cory catfish and a betta is possible with the optimal setup.

Providing a large tank with lots of plants and hiding spots reduces the risk of aggressive behavior.

Avoid stress triggers by keeping your tank clean and testing water parameters regularly.

All bettas have different personalities. Do not force an angry betta to live in a community tank.

Have a backup plan if things don’t work out with your corys and betta fish.