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9 Reasons Your Fish Is Swimming In Circles Dying!

With fish keeping gaining so much popularity over the last few years, there are a huge number of people who are brand new to the hobby experiencing a number of problems for the first time and asking for help on what’s happening in their tanks.

We have answered a huge number of these questions over the last couple of months but today’s article is going to be going over why your fish is swimming in circles while dying.

We have seen a number of people reaching out about this over the last couple of weeks and we wanted to publish this article because some of these issues in your tank can quickly and easily be fixed.

Provided you catch the problem quickly enough, you should easily be able to save the fish and in most cases, it should be able to make a full recovery but the longer you leave the problem, the worse it will get and the more difficult it will be to fix.

Why Your Fish Is Swimming In Circles Dying!

Here is a short list going over the most common causes of a fish swimming in circles dying but we will cover them all in more detail later in the article:-

  • Ammonia Poisoning!
  • Whirling Disease!
  • Swim Bladder Disorder!
  • Not Enough Oxygen!
  • Dropsy!
  • Stress And Anxiety!
  • Water Flow Too High!
  • Issues With pH Levels!
  • Internal Parasites!

There are some less common causes of a fish swimming in circles that are so rare that they are usually not even worth checking for in your fish though.

We will not be taking a more detailed look at each of these issues to try and help our readers work out why their fish is swimming in a circle while dying.

Ammonia Poisoning!

One of the most common issues that we see people running into is ammonia poisoning and in some cases, it can cause your fish to swim in circles constantly.

This happens when the levels of ammonia in your tank get too high and it can quickly kill off your fish if you do not act fast enough.

The good news is that this problem is relatively easy to fix as long as you catch it early enough.

You will need to do a water change to bring the levels of ammonia back down to a safe level and we would also recommend using an ammonia remover to help speed up the process.

Ammonia poisoning is usually caused by overfeeding your fish or by not cleaning your tank often enough.

We would recommend doing a partial water change every week to help keep the levels of ammonia under control.

Whirling Disease!

Whirling disease is a rare condition that can affect both fresh and saltwater fish but it is much more common in freshwater tanks.

The disease is caused by a parasite that attacks the spinal cord of the fish and it will cause the fish to swim in circles.

In most cases, the fish will eventually die from the disease but there are some treatments that can be used to try and save the fish.

The first thing that you need to do is to remove the sick fish from your tank and put it into quarantine.

You will then need to treat the fish with a medication that is designed to kill off the parasites.

Once the parasites are gone, the fish should start to recover but it may never be able to swim properly again.

Swim Bladder Disease!

Another common issue that can cause your fish to swim in circles is swim bladder disease.

This is a condition that affects the swim bladder of the fish and it can be caused by a number of different things.

The most common cause of swim bladder disease is constipation but it can also be caused by a bacterial infection or by a physical injury.

The good news is that swim bladder disease is relatively easy to treat and most fish will make a full recovery provided you try to treat the fish as soon as possible.

Not Enough Oxygen!

If your fish is swimming in circles and dying, it could be because there is not enough oxygen in the water.

This is usually only a problem in larger tanks but it can happen in smaller ones as well if the tank is heavily stocked.

The best way to fix this problem is to add an air stone to your tank and to make sure that you are doing regular water changes but live plants are an excellent way to add more oxygen to your tank too.


Dropsy is a condition that can be caused by a number of different things but it is most commonly caused by a bacterial infection.

The symptoms of dropsy include swelling of the body, scales that stand away from the body, and a fish that swims with its head tilted down.

This can sometimes cause the fish to slowly swim around in a circle but the bloated body of the fish will often make it obvious that dropsy is the problem.

Dropsy is fatal in almost all cases but there are some treatments that can be used to try and save the fish but you do have to implement the treatment plan within hours of noticing the dropsy or it will usually be too late to save the fish.

Stress And Anxiety!

Stress and anxiety can also cause a fish to swim in circles in some cases, especially in smaller aquarium tank sizes.

This usually happens when the fish is in a new environment or when there has been a change in the tank such as a new piece of decoration being added.

The good news is that this problem is usually temporary and the fish will eventually get used to the new tank and stop swimming in circles.

If the fish is still swimming in circles after a few days, you may need to increase the size of the tank or add more hiding spots for the fish to help reduce its stress levels.

Water Flow Too High!

Another common reason why a fish may swim in circles is because the water flow in the tank is too high.

This can be caused by a number of different things but it is usually due to the filter being set on too high or because there are too many air bubbles in the tank.

The majority of the time, this will not actually cause serious problems with your fish and it will not be dying but it may be pushed onto its side if the water flow is high enough in your tank.

More often than not, simply turning the water flow levels down will be enough to stop the problem within minutes.

Issues With pH Levels!

Another common reason why your fish may be swimming in circles is because there are issues with the pH levels in your tank.

The ideal pH level for most aquarium fish is between 6.5 and 8 but some fish do prefer it to be a little higher or lower than this range so always check the specific levels for the species you are keeping.

If the pH levels in your tank are outside of the ideal range, it can cause stress and anxiety in your fish which may lead to them swimming in circles.

The best way to fix this problem is to use a pH test kit to check the levels in your tank and then add some chemicals to raise or lower the pH as needed.

Internal Parasites!

Internal parasites can also be a problem for aquarium fish and they are usually the result of eating infected food or being in contact with an infected fish.

The most common symptom of internal parasites is a fish that rubs itself against objects in the tank or scratches itself on the gravel.

However, this is not always the case and some fish may swim in circles if they are infected with parasites.

The best way to treat this problem is to use a medication that specifically targets internal parasites but you may need to increase the level of filtration in your tank to remove all of the parasites from the water.