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Why Is My Angelfish Swimming Upside Down? (Plus Treatment)

Why Is My Angelfish Swimming Upside Down? (Plus Treatment)

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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.

Adding angelfish to your fish tank is a very good idea. You’ll need to make sure that they’re compatible with the other fish that are in the tank already, but they add a lot of beauty to any aquarium.

These beautiful fish are popular for a reason. They’re very lively, and it’s a ton of fun to watch them swim around.

If you’ve recently added some angelfish to your fish tank, then you might be surprised to see one of the angelfish swimming upside down. This is certainly going to look weird, and you might be wondering if there’s something wrong with the fish.

Why would an angelfish swim upside down? Is this normal behavior or should you be concerned that the fish is sick?

Continue reading to learn more about fish swimming or floating upside down. This will help you to know what you should be doing.

The Fish Almost Surely Has Swim Bladder Disease

Oranda Goldfish Near Surface With Swim Bladder Issue
Oranda Goldfish Near Surface With Swim Bladder Issue

Sadly, your angelfish almost surely has swim bladder disease if it is swimming upside down. Generally, when you see a fish swimming upside down, it’s going to be at the top of the tank or at the bottom of the tank.

If you’re sure that the fish is still alive because it’s actively moving around, then it’s because the fish has swim bladder disease. This disease impairs the buoyancy of the fish and makes it so that it can’t swim around normally.

When the swim bladder malfunctions, fish lose the ability to swim, and they wind up floating uncontrollably. Needless to say, this is a serious problem and it needs to be addressed right away for the sake of the fish.

Where the fish will be while experiencing swim bladder issues won’t always be the same. Some fish will be upside down or sideways at the bottom of the fish tank.

Most seem to float at the top of the tank without truly being able to control where they’re going. If you want the fish to get back to normal, then you’ll need to talk to an exotic veterinarian to start treatment options.

Will Swim Bladder Disease Kill a Fish?

Interestingly, swim bladder disease is not lethal on its own. You might expect that this condition would kill a fish due to how its swimming is impaired.

It’s true that the fish might not survive, but this isn’t directly because of the swim bladder disease. You should know that swim bladder disease is actually a symptom of another condition.

Fish that get some other type of disease or who are experiencing other problems might develop swim bladder disease. If the fish dies, then the death is attributed to the other condition.

Although swim bladder disease is a serious problem, it isn’t the direct cause of death. Many things could kill fish that are experiencing problems such as this, though.

If a fish can’t control how it swims, then it’s not going to be able to reliably eat. Also, other fish could choose to try to eat the fish while it’s upside down and vulnerable.

What Is the Cause of Swim Bladder Disease?

Swim Bladders From Perch on a Blue Surface

Swim bladder disease is caused by a deformation of the swim bladder. This could mean that there is a temporary deformation of the swim bladder, but it could also be permanent.

When the swim bladder is narrowed or deformed, then the impacted fish will no longer be able to balance its body. This means that your angelfish will lose its ability to swim around normally.

There are several different reasons why this can happen. Generally, the basic reason why the swim bladder becomes deformed has to do with swelling in the belly.

The reason for the swelling can differ, though. For example, some fish might experience belly swelling issues due to being injured.

Constipation issues have been known to cause issues with swim bladders. This makes sense due to the fact that swelling in the belly area is the major factor that deforms the swim bladder.

It’s also possible for an angelfish to experience swelling due to having a bacterial infection. Even common problems such as swallowing too much air can wind up causing swim bladder disease.

Getting the fish back to normal is going to involve determining what is wrong. It’s often going to be easiest to consult an exotic veterinarian that has experience helping with issues such as this.

Treatment Options

Bowl of Canned Peas on a Table

To start, you’re going to want to move the fish that is experiencing swim bladder issues to a separate tank. People often refer to quarantined tanks as “hospital tanks.”

This will make it so that you have control over the environment that the fish is placed in. You also won’t have to worry about the other fish while you’re trying to figure out what’s going on.

You’re going to need to pay attention to the water parameters as always. Ensure that you keep the water quality where it needs to be so that the fish can remain as healthy as possible.

With that taken care of, you’ll need to figure out what is wrong with the fish. If the fish is experiencing constipation issues, then you can try to get the fish better by feeding it food that is rich in fiber.

Some try to treat constipated fish by fasting them, but it’s likely going to be faster to feed the fish fiber-rich foods. The fiber-rich foods should help the fish to clear everything out of its digestive system, and this will allow it to go back to normal.

If the fish has a bacterial infection, then you’ll want to give it antibiotics to help it get over the infection. The problem is that it can be quite hard to know whether the angelfish has a bacterial infection issue or not.

This can be tested by testing the fluid in the fish’s bladder. You can get the sample using a needle, but you shouldn’t do this unless you know what you’re doing.

You would need to take the angelfish to the exotic veterinarian to get the test done. Then you can confirm if the fish has a bacterial infection.

If the fish does have an infection, then the vet will be able to recommend antibiotic treatment options. After treating the fish, it should get better and start swimming normally again.

It isn’t wise to just start putting antibiotic treatments in the tank without knowing that the fish has an infection. It’s possible that antibiotics will do more harm than good, and this is why you must only use them when necessary.

Sometimes Fish Will Have Birth Deformations

Neon Tetra With a Body Deformity
Neon Tetra With a Body Deformity

It’s worth noting that sometimes fish will have birth deformations. This means that the swim bladder issue could be occurring due to the fish being born with the problem.

This doesn’t happen very commonly, though. As far as angelfish go, this would be a fairly unusual situation.

However, it is seen as a slightly more common thing in fish such as bettas and goldfish. It certainly could be the case that angelfish will experience birth deformities, though.

Angelfish are among the most popular pet fish in the world because of how nice they look. They’re bred to look as beautiful as possible, and this involves a lot of selective breeding.

Sometimes the gene pool is a bit thin, and this can lead to some of the fish coming out with deformities. A swim bladder deformity is a possibility even if it isn’t an incredibly common one.

There isn’t anything that you can do for a fish that has been born with some type of permanent deformity. Many choose to euthanize fish that come out this way.

What About Permanent Swim Bladder Injuries?

There could be a situation where a fish will be injured enough to deform the swim bladder. In some cases, the swim bladder deformity could wind up being permanent.

You can’t treat a permanent swim bladder deformity. If the swim bladder is never going to return to normal, then you might want to simply euthanize the fish.

It might seem cruel to euthanize the fish, but it’s likely the kindest thing that you could do for it. Otherwise, the fish would just slowly die due to not being able to swim and care for itself properly.

These injuries sometimes occur due to fish fighting with other fish. You should be careful not to put incompatible fish in the tank with your angelfish.

It’s also possible for injuries to happen when transporting the fish home from the store. This is why it’s imperative to protect the fish and be careful when moving it to its new home.

Final Thoughts

Pair of Angelfish in a Tank With Driftwood and Rocks in the Background

Knowing what causes swim bladder disease will help you to understand what you should be doing. It’s not good for an angelfish to be floating or swimming upside down because this means that it is going through a very tough time.

If the angelfish is just bloated or experiencing a bacterial infection, then you should be able to clear things up. It’ll be necessary to either give it fiber-rich food or to treat it with antibiotics depending on what is wrong.

The easiest thing to do is to ask the veterinarian what is happening. You should be able to determine exactly what is wrong with the fish.

Since swim bladder disease can occur because of physical injury and natural birth defects, it’s possible that there is nothing you can do. In this case, euthanizing the fish is the kindest course of action.

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Sunday 30th of April 2023

I have koi angelfish just today it started showing signs of the swim bladder disease signs. I quickly put him into a smaller tank. He is upside down right now and when he tries to swim he is on his side. All the other fish are perfectly fine and so was he this morning. I have to try to save him I need advice. Please help

Keith DePugh

Sunday 30th of October 2022

My angelfish was gulping air & I think now has swim bladder issue. I Did a 25% water change & added an air stone. Is there anything else I should be doing? The rest of the fish seem fine. Thanks


Tuesday 1st of November 2022

It sounds like you took the right steps if your angelfish was gulping air. As far as treating a swim bladder issue, depending on the cause, the treatment could be anything from feeding it a pea to using antibiotics. It might be worth monitoring the angelfish for a couple of days to see if there's improvement from the water change and air stone.