Skip to Content

5 Possible Reasons Why Your Cory Catfish Died Suddenly

5 Possible Reasons Why Your Cory Catfish Died Suddenly

Share this post:

This post is written to the author's best knowledge and is not intended to be used in place of veterinary advice. In addition, this post may contain affiliate links. As an Amazon Associate I earn from qualifying purchases.

Cory catfish are certainly some of the finest community tank fish that you can own. They’re so peaceful, and they’re also considered to be very easy to care for.

Most types of cory catfish are very hardy overall. They aren’t so sensitive that they will be hard for beginners to learn how to care for.

You shouldn’t let the hardy nature of these fish lull you into a false sense of security, though. Some have noted that they’ve had cory catfish die suddenly in their fish tanks.

If your fish have died for seemingly no reason, then you’re likely wondering what happened. Keep reading to learn more about this topic so that you might figure out how to better keep these fish alive in your fish tank.

1 – Water Quality Issues

Man Holding PH Tests for Freshwater Aquarium

Water quality issues are likely to blame when a cory catfish dies suddenly. One thing that you should know is that these fish are susceptible to changes in the water chemistry.

Specifically, they’re going to have a hard time if you allow the ammonia, nitrate, and nitrite levels to get too high. High nitrate levels will make it very hard for the fish to breathe, and this will sometimes cause cory catfish to die suddenly.

Generally, ammonia, nitrate, and nitrite levels get too high when you’re not monitoring the water parameters properly. There is a chance that you might not be checking the pH balance often enough to ensure that everything is in order.

It’s also a likely indication that you’re being too relaxed when it comes to water changes and keeping the fish tank clean. Ideally, you should be changing 15% of the water each week to protect the fish and keep the tank clean.

Adjusting your habits should allow you to keep the water quality high so that your fish will be able to do well. It isn’t necessarily hard to keep the water quality in the right range, but you do need to put in the effort.

Keep in mind that it’s harder to keep a smaller fish tank clean. There could be other issues that are negatively impacting the water quality.

For example, keeping too many fish in a small fish tank can make the water dirty. Too much fish poop in a small tank can be very problematic.

You never want to put cory catfish in fish tanks that are too small. They need tanks that are big enough so that they will have space to move around.

It’ll likely be best to keep cory catfish in 30-gallon fish tanks. This is especially true because you’re supposed to keep them in groups.

2 – Loneliness

School of Bronze Corydoras in Planted Freshwater Tank

As mentioned above, cory catfish are supposed to be kept in groups. You’re not going to have an easy time keeping the fish alive if you are keeping too few of them in your tank.

In the wild, these fish are social and they live with others of their kind. Cory catfish do best in fish tanks when you keep at least six of them.

Some have noted that cory catfish have died of loneliness in their fish tanks. Keeping just one cory catfish in a fish tank is considered to be cruel.

Likewise, it’s not good to keep only two or three of them in an aquarium. You want a larger group of them to keep the social dynamics right and to ensure that the fish feel comfortable in the tank.

If you don’t have enough room for six fish, then it’s likely best not to buy cory catfish. You might want to wait until you have enough room for these fish so that you can care for them in the best way.

3 – Disease

Freshwater Angelfish With White Spots Indicative of Ich Disease

Disease could easily cause cory catfish to die suddenly. If you’re not a fish tank owner who spends a lot of time observing the fish, then you might not have noticed that something was wrong until it was too late.

Like other fish, cory catfish are susceptible to many different diseases. Some of them are going to be more likely to kill the fish than others.

Ich is a common disease that cory catfish have to deal with. This is something that you’re likely to notice before it kills the fish since it causes obvious white spots to appear on the fish.

The fish could also develop some other type of infection that might be harder to notice, though. Sometimes you won’t see physical differences on the fish, but you might notice behavioral differences if you pay attention to the fish.

If the fish seems sluggish or if it isn’t eating normally, then you should take that as a sign that something is wrong. It pays to be an observant and proactive fish tank owner.

Catching issues with sickness and disease early will give you the best chance of saving the fish. Do your best to keep your eyes open for potential issues.

4 – Stress

Small Glass Fish Bowl With Blue Background

Stress is something that might cause fish to die in some situations. Granted, it would likely take a lot of stress to make a fish die suddenly.

Cory catfish can become stressed for many different reasons. You might see them get stressed if you don’t set up the tank properly for them.

These fish need to have substrate at the bottom of the tank that they can sift through. It’s best to use sand since that won’t injure the fish.

Cory catfish like to be able to hide at the bottom of the aquarium as well. It’s recommended to put plants in the tank to make them feel as comfortable as possible.

They also don’t like being put in very small fish tanks. It makes them feel uncomfortable, and it can lead to strange behavioral issues in some circumstances.

If the environment is not right at all for the cory catfish, then some of them might start dying eventually. You should try to set the fish tank up properly for these fish to make them feel more at home.

5 – Lack of Care

Various Types of Food for Aquarium Fish

Lack of care can also kill the fish pretty easily. Have you been feeding the fish?

Forgetting to feed the fish could eventually lead to death. You also might not be feeding the fish the right food.

Cory catfish aren’t picky eaters since they’re omnivores. Even so, it’s worth considering whether you’ve been caring for the fish properly.

Check the care requirements for the type of cory catfish that you’re keeping in your aquarium. If there’s something you’re doing wrong, then maybe that could be why the fish died suddenly.

Why Is My Cory Catfish Dying?

As you now know after reading all of the information above, there are many possible reasons why cory catfish might die. The most likely scenario involves problems with water quality.

Often, beginners make mistakes when taking care of the fish tank. You might not be doing regular water changes, and this will lead to the tank becoming too dirty.

The elevated ammonia, nitrate, and nitrite levels are likely what killed the fish. That’s not to say that this is what causes cory catfish to die suddenly 100% of the time.

It could also be related to issues with loneliness, not feeding the fish properly, disease, and other such problems. You’ll just have to examine how you’ve been caring for the fish to get to the bottom of the situation.

Now that you know about common reasons why these fish will die suddenly, it should be easier to keep them alive. Knowing what mistakes to avoid can be very beneficial.

Share this post: