betta swimming erratically

Is Your Betta Swimming Erratically: Causes and Treatments

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As betta fish specialists, we know how concerning it can be to see your betta suddenly swimming erratically in the water. Erratic swimming often indicates an underlying health condition or water quality issue.

Some of the most common causes of erratic swimming are swim bladder disorders, low oxygen levels, and ammonia poisoning, but there are many other possible causes, too.

Here we’ll look at some of the most common causes, so you can diagnose and treat the issue as swiftly as possible.

Key Takeaways

  • Erratic swimming in betta fish is often a sign of stress, poor tank conditions, or disease such as swim bladder disorder. In other cases, it might be a harmless personality trait.
  • To find out if there’s a problem, test your tank’s water as soon as possible and check your fish for signs of disease.
  • If you can’t diagnose the issue, consider consulting an exotics vet or ask an expert on an online betta fish forum.

betta fish swimming erratically in aquarium

How Can You Tell if Your Betta Is Stressed?

All animals, including fish, can become stressed. Fish usually become stressed in response to the quality of their environment, like incorrect water parameters, disease, or even incompatible tank mates.

A few signs of a stressed betta are lethargy, lack of appetite, loss of color, heavy breathing, and erratic swimming. Female bettas may even develop stress stripes.

A healthy betta will have bright colors, flowing fins, and a bold personality. If your fish just doesn’t seem to be lively, something could be wrong.

What To Do if Your Betta Fish Is Swimming Erratically

Because erratic swimming is often a sign of a more serious problem, it’s important to work quickly to attempt diagnosis and treatment of the issue.

First of all, test your tank’s water to see if water parameters are at the correct levels or whether ammonia or nitrite poisoning has occurred.

Look for signs of common diseases and tank problems like the ones we discuss below to see if you can find a cause. If there’s no apparent problem, it might just be a genetic predisposition or an unusual personality trait!

Why Is Your Betta Fish Swimming Erratically?

There are a few reasons why your betta fish might be swimming erratically. Let’s look at some of the most common causes:

Poorly Acclimated

Giving your fish a good start in your aquarium begins with proper acclimation. Acclimation is the process by which you get your fish used to your aquarium water (mainly pH and temperature) when transferring them from the pet store.

Popular methods of acclimation include floating the fish bag and drip acclimation. If this process is done too quickly, it could cause your fish to go into shock and eventual death.

Acclimation should never be rushed, even if receiving livestock in the mail. Make sure temperatures and pH match before introducing your new fish into your system.

Water Parameters

If your fish just started swimming erratically and you’ve had it for a while, then you will need to check water parameters. A sudden behavior change usually indicates that there has been a change in the system and/or poor water quality.

Ideally, water parameters should test 0 ppm ammonia, 0 ppm nitrite, and <10 ppm nitrate. Ammonia and nitrites are especially important as they can become lethal even at low levels.

Lack of Oxygen

Most oxygen is introduced into an aquarium through gas exchange at the water’s surface. If there is not enough oxygen in your aquarium, your fish might struggle to breathe.

Periods of frantic swimming may occur as your fish is searching for more oxygenated waters.

Increasing filter flow, or adding an airstone are good ways to increase dissolved oxygen levels in the water. Just be careful not to make the filter flow so strong that your fish struggles to swim, as this is another common cause of stress in betta fish!

Disease and Other Impairments

Your fish might also be struggling with a disease, such as a bacterial infection, or parasite.

Almost all aquarium illnesses share the same main symptoms: lack of appetite, lethargy, loss of color, and rubbing against decorations.

A common disorder that causes erratic swimming in betta fish is swim bladder disease.

Swim Bladder Disease

Swim bladder disease is the result of many factors impeding your fish’s ability to maintain an upright position in the water.

Some symptoms include the fish swimming on its side or upside down; you might notice that your fish is swimming frantically in an attempt to right itself. It is also possible that the abdominal area will also be distended and the back will be curved.

Swim bladder disease can be caused by overfeeding, constipation, gas, genetics, or poor water quality. All of these factors could cause the swim bladder to become compressed and unable to regulate itself.

Neurological Damage

Sadly, fish can also suffer from neurological damage just like any other animal can.

Whether this impairment was caused by an injury or a parasite, the motor skills of your fish can become compromised. Circular swimming and frantic swimming may result.

betta fish swimming towards front phase of aquarium


Betta fish display their best colors and personalities when they’re given a high-quality diet. Primarily carnivores, they need a good source of protein-rich foods that help keep them in their best shape.

A low-quality diet could lead to many types of abnormal behavior. If you notice that your fish starts to act differently, make sure to reassess the ingredients in its food, check for abdominal bloating, and monitor feeding times.

Old Age and Poor Vision

Fish get old. As with other bodily functions, motor skills can start to deteriorate with time.

Old betta fish also sometimes develop cataracts or lose the quality of vision. Poor eyesight could lead to bumping into decorations, but there is sadly nothing you can do but make navigating the tank a little easier for an old friend.

Incorrect Lighting Schedule

I’ve found that one aspect of the tank environment that some novice aquarists often neglect to get right is the fish tank’s lighting schedule. Fish that are constantly exposed to aquarium lights may develop unusual behavior such as erratic swimming.

Just like us, betta fish need both day and night to function normally. Install a timer switch to give your fish between 9-14 hours of lighting time, followed by a period of darkness when they can sleep.

Exploring Further Causes

While we’ve covered some of the most common reasons for erratic swimming, it’s a fairly common symptom of many issues with fish health or tank conditions.

Check out the health and diseases section of our website to learn more about potential betta health conditions.

If you’re still unsure about the cause of the problem, consider contacting an exotics vet or posting a video on an established betta fish forum for an expert opinion.


Erratic swimming can often indicate an underlying health issue, so testing your tank water and attempting to diagnose the problem as soon as possible could be critical for your fish’s wellbeing.

In other cases, it could just be a particular personality or genetic trait of your betta that it can happily live with for years to come.

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