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3 Common Causes of a Cory Catfish with Red Gills

3 Common Causes of a Cory Catfish with Red Gills

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

You very likely love your cory catfish. These are fantastic fish that are going to add a lot of charm to your fish tank.

Not only are these fish great community tank fish, but they’re also fairly easy to take care of. That doesn’t mean that things can’t go awry when mistakes occur, though.

Are you noticing that your cory catfish seem to have red gills? This obviously isn’t normal, but you might not be sure what it means.

What is going on when your cory catfish has red gills? Continue reading to get all of the information that you need.

1 – High Ammonia Levels

Measuring the pH in a Fish Tank

The most likely thing that is happening is that your fish tank has high ammonia levels. When you don’t monitor the pH balance of the tank and keep it clean things like this can happen.

Over time, the ammonia, nitrate, and nitrite levels will rise when you’re not doing regular tank maintenance. This can be very harmful for the fish for many different reasons.

When the ammonia levels get too high, it can irritate the gills of the cory catfish quite a bit. The red gills that you’re seeing are likely signs that the ammonia is burning the gills and the skin of the fish.

Of course, you’re going to need to solve this issue as fast as possible for the sake of the fish. Failure to address the problem can lead to the cory catfish dying.

It’s also important to understand that heightened nitrite levels can poison and kill cory catfish. Some types of cory catfish are even more vulnerable to high nitrite levels than others.

Knowing this, you’ll want to endeavor to keep a close eye on the water parameters. Regularly test the water using a pH balance testing kit.

This will ensure that you can address fluctuations before they get out of hand. Being a more proactive fish tank owner will be necessary if you want your fish to stay healthy.

2 – Malnourished Fish

Corydoras Feeding

Some enthusiasts suggest that red gills could just be a sign that the fish is in bad shape. It might be the case that the fish aren’t getting the necessary nutrients to stay healthy.

Are you feeding the fish normally? If you’ve been making mistakes when feeding the cory catfish, then this could lead to issues with discoloration near the gills.

It’ll be worthwhile to look into what you’re feeding the fish. Cory catfish aren’t picky eaters, but you are supposed to feed them quality foods that will give them the nutrients that they need to grow strong.

Most people feed cory catfish sinking nutrition pellets on a daily basis. They supplement the diet of the fish with things such as algae rounds, fish flakes, freeze-dried bloodworms, and veggies such as zucchini.

If you haven’t been feeding your cory catfish a varied diet, then you might need to try changing things up. You might have been feeding the fish too infrequently as well.

The best thing to do when caring for cory catfish is to feed them twice per day. It’s said that feeding the fish twice per day and giving them as much as they can eat in three minutes is the right way to go.

You can feed the fish once per day if that’s more convenient for your schedule. It’ll be necessary to give them as much as they can eat in five minutes if you are only feeding them once per day.

3 – Parasites

Parasites might cause the cory catfish to experience some type of gill irritation. This can make the gills have a red appearance depending on what is wrong.

It’s more likely that you’re dealing with ammonia issues, but it’s worth considering whether parasites could be the problem. You might need to look for other symptoms and signs that your fish are infected.

Either way, the problems that lead to fish having red gills are usually related to poor water conditions. Fish will generally not become infected by parasites unless they’re living in dirty water.

It’s likely that you haven’t been taking the time to do water changes. If you’ve been skipping water changes, then that could have been enough to make the water quality poor enough to negatively impact the fish.

Try to do a better job of keeping the fish tank clean to avoid problems like this. It’ll help the fish to stay healthy under your care.

General Care Advice

Group of Cory Catfish Swimming Together

To try to keep things like this from happening, there are many things that you should do. One of the most important things to remember is to avoid overcrowding the fish tank.

It’s a lot easier for things to go wrong when the fish tank is crammed full of fish. You never want to put too many fish in a tiny fish tank.

Cory catfish need to be kept in groups of six or more to be happy. This means that you’ll need a tank that can comfortably fit that many fish for things to be okay.

Depending on the type of cory catfish that you’re buying, it might be necessary to buy a larger tank. For some cory catfish, a 30-gallon tank will be prudent, but you might want something even larger.

This is especially true if you plan to put other types of fish in the aquarium. You want to ensure that all of the fish have enough room to be comfortable.

When too many fish are kept in a small tank it will stress the fish. Also, it makes the water dirtier due to there being too much fish poop in a small area.

You’ll have a simpler time cleaning a larger tank than one that is too small. It’s a simple adjustment to make that can keep your cory cats safe.

It’s also best to avoid overfeeding the fish. Feeding the fish too much will cause them to poop way too much, and this negatively impacts the water quality.

Always feed your fish the right amount of food without overfeeding them. If you overfeed them once or twice, it likely won’t be a huge deal, but you want to try to keep things in the right range for safety purposes.

Plus, overfeeding fish can make them constipated. This has the potential to cause swim bladder issues, and that can be troublesome for the fish.

Final Thoughts

You should have a much better idea of what is going on with your cory cats now. If your cory catfish appear to have red gills, then that’s a sign that something is wrong.

It most likely means that your fish tank has elevated ammonia levels. High levels of ammonia will burn the skin and gills of the cory catfish.

Another possibility is that your fish could be dealing with some type of parasitic infection. Fish become susceptible to such things when being kept in poor water conditions.

Malnourished fish can also have gills that appear to be discolored. You might want to ensure that you’re feeding the fish properly.

Do your best to take care of any problems that are present in the fish tank. You should be able to turn things around with enough effort.

Moving forward, you’ll be able to do a better job of looking out for your cory cats. They will stay healthy if you put in the effort to give them optimal care.