betta fish swimming erratically in fish bowl

Betta Fish Swimming Erratically? Here’s Why

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The last thing you want to see is your fish swimming frantically around your tank and you have no idea what’s causing it. Erratic swimming is usually a sign that something is wrong either with the aquarium water or with the health of your fish. There are a few likely reasons for this behavior, all of which are relatively easy to fix.

Keep reading to find out why your betta fish is swimming erratically and how to treat the problem!

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 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; it is also important to note that each fish has its own personality and erratic swimming from time to time could just be a characteristic of your fish.

Why is your betta fish swimming erratically?

betta fish swimming erratically in aquarium

There are a few reasons why your betta fish might be swimming erratically. First, you will need to look at how your betta fish was first introduced and then at water quality. If everything is testing the way it should, then you might be dealing with a disease. If everything still checks out after that, then you might just have a silly betta!

Poorly acclimated

Giving your fish a good life starts 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. One of the signs that you acclimated your fish too quickly is erratic swimming. This is done in an effort to escape this water in hopes of finding more similar parameters.

Acclimation should never be rushed, even if receiving livestock in the mail. Make sure to allow temperatures and pH to fully 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 change in behavior 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 nitrates are especially important as they can become lethal at relatively low values; nitrate can also become toxic at extreme levels, though this is usually a sign that something else is wrong in the system too.

Ammonia and nitrite poisoning

A new fish should never be introduced to a cycling tank as it has poor water quality with traces of ammonia and nitrite. Ammonia can quickly burn gills and internal organs at low values. Nitrite can also bind with hemoglobin, depriving fish of oxygen in their system. This is known as ammonia poisoning and nitrite poisoning respectively.

Both of these situations can result in your fish gasping for air at the surface of the water, violently scratching against decorations in the aquarium, and swimming frantically around the tank. Use a test kit to check parameters and watch for changes in behavior as well as inflamed gills and other sores on the body. Perform water changes until more optimal conditions have been met.

Lack of oxygen

Most oxygen is introduced into the aquarium by way of surface agitation. However, bettas can struggle in higher water flows and too much agitation can lead to injury; a delicate balance is needed to ensure that enough gas exchange is happening in the tank without making it more difficult for your fish to swim.

If there is not enough oxygen in your aquarium, fish might struggle to breathe and rest on the substrate as a result. Periods of frantic swimming may occur as your fish is searching for more oxygenated waters. Unfortunately, there is not a lot of time to correct this problem. It is recommended to have plenty of live plants to perform photosynthesis and an air stone on hand in case the power goes out or if equipment breaks.

Disease and other impairments

If water quality is good, then your fish might be struggling with disease, infection, or parasites. Almost all aquarium illnesses share the same main symptoms: lack of appetite, lethargy, and rubbing against decorations. However, stress might also show itself by causing your fish to swim frantically around the tank.

Swim bladder disease

The swim bladder is the organ designed to maintain buoyancy in the water column for most fish species. Swim bladder disease is the result of many factors impeding on your fish’s ability to correctly align itself. Some symptoms include the fish being unable to float stationary in the water column, sometimes swimming on its side or upside down; you might notice that your fish is swimming frantically in attempts to constantly upright 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, or poor water quality. All of these factors could cause the swim bladder to become compressed and unable to correctly regulate itself. Swim bladder disease could also be the result of irritation caused by parasites, bacterial infection, or damage taken from a fall or other injury. Sometimes, the fish is born with a defect that compromises the efficiency of the swim bladder.

There are many different methods for treating swim bladder disease, though sometimes the condition is permanent. If you find your fish swimming like it can’t control its alignment, make sure water quality and water temperature are optimal. Over the course of three days, do not feed your fish and slightly raise the water temperature to about 80-82° F (26.7-27.8° C). After this period, try feeding your fish thawed and deshelled peas for the next few days. Once you notice that your fish is making bowel movements regularly, revert back to regular fish food, preferably a kind that does not float.

As mentioned before, swim bladder disease is sometimes permanent. If you have done everything that you can for your fish and it still can’t swim correctly, it might be time to humanely euthanize it.

Neurological damage

Sadly, fish can also suffer from neurological damage just like any other animal can. Whether this impairment was caused by a fall or a parasite, the motor skills of your fish can become compromised. With this, circular swimming and frantic swimming might occur. The best thing to do in these cases is to make the aquarium injury-proof and as handicap-friendly as possible.


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 constipation and overall 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

Fish get old. As with anything, fine motor skills start to deteriorate with time. Old betta fish have even been known to develop cataracts or lose the quality of vision. Poor eye-sight could lead to some embarrassing senior moments with bumping into decorations, but there is sadly nothing you can do but make navigating the tank a little easier for an old friend.

Other Reasons

betta fish swimming towards front phase of aquarium

If your betta fish isn’t swimming erratically due to poor acclimation, water parameters, or disease and other impairments, then it could potentially be a one-time-thing.

Some hobbyists have seen their betta fish get caught up in decoration or plant and exert themselves to get away; they then stay pretty skittish for the next few hours as they think they are in danger. Other hobbyists have seen their betta fish chase after their own reflection, especially if it’s a new betta fish. This can be solved by covering the sides of the tank and allowing the fish to fully acclimate.

If you notice that your betta is fighting its own reflection after having owned it a while, this might be due to a lack of enrichment in the tank. Betta fish can have great personalities, and some hobbyists have even had luck teaching them how to perform various tricks and tasks. If you notice that your betta has lost its appetite, sits at the bottom of the tank, or has random bursts of energy that cause it to zigzag around the tank, it might be worthwhile to buy some enrichment items.

Otherwise, this behavior might just be a characteristic of your fish. Bettas are known to be very bold fish in terms of color and personality. Your betta fish may just like swimming around the tank at high speeds sometimes! However, this behavior should not be every day and will need to be looked into more if it persists.

Note: If you have an especially active betta fish, make sure to invest in an aquarium lid so that it can’t easily jump out of the tank!


Seeing your fish swim aimlessly around the tank can be a worrying sign. Usually, the underlying problem can be easily fixed. This might be a problem regarding acclimation, water parameters, or disease and other impairments. Of course, if everything in your tank is testing the way it should, then your betta fish swimming erratically might just be the personality of your fish!

If you have any questions about why your fish is swimming funny, normal betta behavior, or have had experience with a similar problem in your own aquarium, don’t hesitate to leave a comment below!

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