Betta Fish Swimming Erratically – Should You Worry?

There’s nothing more worrying than when you notice your betta fish swimming erratically. There is a whole range of conditions that can cause this, some of them good and some of them extremely bad.

So keep reading to find out:

  • If it’s the water quality or if your fish is sick.
  • What erratic swimming looks like and the causes of it.
  • And most importantly, the best steps to take moving forward!

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What Does Swimming Erratically Look Like?

When you first notice your betta swimming in an odd manner, it’s perfectly normal to panic. Because good or bad, there is going to be a reason for erratic swimming. And there are so many different types of erratic behavior your betta may exhibit. So it can be hard to really find the answer. Some common swimming behaviors that are a sign of trouble are:

  • Swimming around in circles.
  • Floating and sticking to the surface of the water.
  • Twirling or swimming in a corkscrew fashion.
  • Swimming upside down.
  • Having troubles swimming to the top or sinking to the bottom.
  • Rubbing or banging into things.

If you notice any of these symptoms then your betta could be in a lot of trouble.

Common Causes Of A Betta Fish Swimming Erratically

If you notice your betta fish swimming erratically, the first thing you need to find out is what’s causing the behavior. Erratic swimming can have many causes ranging from neurological damage to water quality, so it’s good to have a base knowledge on all the common causes.

Swim Bladder Disease

While not actually a disease of the swim bladder; swim bladder disease is the name given to problems with a bettas swim bladder. This can be caused by all sorts of different issues such as constipation, bacterial infections, birth defects, intestinal parasites, and high nitrate levels.

(If you want to know more about swim bladder disease such as the symptoms, how to treat it and how to prevent it then check out this article!)

Nervous System Disorders & Neurological Damage

If your fish is exhibiting signs of erratic swimming, especially circling patterns or whirling, then it could be a nervous system disorder or neurological damage. This could be a birth defect. However, it could also be caused by bacteria (such as tuberculosis) and parasites.


With a whole host of parasites that can cause harm to your betta fish, it’s no surprise that they can be the result of erratic swimming. Parasites can often cause your betta to rub against things in an odd fashion. However, luckily, most parasites can be spotted and if seen early enough, treated as well. (Some common parasites include anchor worms, gill flukes, ich, and velvet.)

If you do think that your betta is suffering from parasites then you should move it to a quarantine tank. (Find out how to set up a quarantine tank.)

Poor Nutrition

In the wild, betta fish are carnivores, so they need lots of meat. So you should make sure your betta is getting all the nutrients it needs. If not, he may become weak or constipated. Both outcomes can affect a bettas swimming capabilities.


Often caused by a lack of oxygen in your betta’s water, hypoxia can cause your fish to swim in an odd way. Most often they will spend a lot of time at the surface of the tank trying to get oxygen. However, it can also be caused by gill disease and anemia.

(Hypoxia can often occur when the water is too warm. Check out the perfect temperature for bettas and why it’s so important!)

Poor Vision

How old is your betta? If they’re getting on in years then their eyesight may be deteriorating naturally. However, poor vision can also be caused by popeye, cloudy eye, and other parasites migrating to the eyes.

Poor Water Quality

And lastly, does your fish tank have good water quality? Bad water quality can cause all sorts of problems including causing a betta fish to swim erratically. To keep your water quality as good as it can be you should do the following:

  • Check the pH level is around 7.
  • Make sure that there isn’t a high ammonia buildup, which can lead to ammonia poisoning.
  • And ensure that there are no sudden temperature changes which can result in temperature shock.

Creating the ideal water conditions doesn’t have to be hard. Especially when you have guidelines that you can follow!)

How To Treat Betta Fish Swimming Erratically?

Because you can’t take your betta to the vet, it’s down to you to diagnose and treat your betta. And with that being said, here are a few of the most common ways bettas swim erratically, and how to treat it.

Betta Swimming Around In Circles

If you notice that your betta is swimming around in circles then there can be a few causes.

  • Your betta could be stressed. If he is new to your tank then for the first few days this could be the problem. Or perhaps he can see his own reflection, in which case he’s swimming in an aggressive manner to ward off the “other” betta fish.
  • If a chemical has been introduced to the water that your betta doesn’t like, then he could be swimming around in circles. If you’ve been using cleaning products or air fresheners around your tank then some might have got in.
  • Perhaps it is a sign of brain trauma as well. Your betta may have hit his head on the glass or a decoration. If this is the case there’s nothing you can do and you’ll just have to wait and see what happens.
  • And lastly, your betta may be swimming in circles if the tank isn’t big enough. You may have heard that bettas survive in 1 gallon of water or less. And that is true, but remember the keyword is survive. For your betta to truly be happy you should consider buying a 5-gallon tank or bigger.

If you notice your betta is swimming in circles then you may want to:

  • Try to reduce any reflection in the tank. You can do this by only turning the aquarium light on when the room is light as well. You could also invest in some aquarium background wallpaper to stick on the inside of your tank.
  • If you think it’s being caused by a chemical in the water you may want to wait a while to see if your betta calms down. If he doesn’t then you may need to perform a water change.
  • And if you think it’s because your tank isn’t big enough then you should consider investing in a bigger tank (best 5-gallon tanks for bettas).

Betta Swimming Upside Down, Having Trouble Swimming, Twirling, Or Swimming In A Corkscrew Fashion

If you notice that your betta is swimming upside down or any of the other symptoms listed above then it is most likely caused by swim bladder disease. Luckily, with the right treatment swim bladder disease is rarely fatal, here are a few common causes:

  • One of the most common causes of damage to a bettas swims bladder is constipation. Most often caused by dried pellets and freeze-dried food.
  • You may be feeding your betta too much and he has now become too bloated to swim properly.
  • If your betta fish is living with other fish or with rough ornaments, then it could have damaged its swim bladder in a fight, or by swimming into something.
  • And obviously, there is a whole range of bacterial infections that can cause swim bladder disease as well.
  • And sometimes, bettas are just born with a defective swim bladder.

How do you treat a betta fish with these symptoms?

  • If you think swim bladder disease is being caused by constipation or bloating then you should stop feeding your betta for 1-3 days. Also if you’re using dried pellets or freeze-dried food then soak them in water to make sure they expand to their normal size before being eaten. And lastly, try feeding your betta daphnia which will act as a laxative.
  • If you think swim bladder disease is being caused by a bacterial infection then you’re going to need to treat your betta with antibiotics.

Rubbing Or Banging Into Things

If you notice that your betta is rubbing against stuff or banging into things then you should be aware of these common causes:

  • Oftentimes rubbing or banging into things can be the result of parasites such as ich, anchor worms, gill flukes, and velvet. The good news is that if this is the case you’ll be able to spot the symptoms of each parasite.
  • If you don’t notice any external symptoms on your betta then it could be caused by ammonia not breaking down fast enough. A high amount of ammonia is more prominent in new tanks or tanks that haven’t had their water changed. Too much ammonia could begin to irritate your bettas eyes, gills, and skin. And often leads to ammonia poisoning.

How Do You Treat These Symptoms?

  • If you think your betta fish swimming erratically is due to parasites then you should treat them with an anti-parasitic like API General Cure or aquarium salt. (What you need to know about aquarium salt.)
  • When you think it’s due to ammonia then you should test the water immediately. You can use any test kit but I love the API Master Test Kit. And if you can’t do that you should begin 25% water changes every day until you can.

For the best results, you should always treat your betta depending on the illness. You can follow these guides to help you out!

Betta Floating At The Surface Of The Tank

Bettas have to go to the surface of the tank to breathe, but they should never be spending all their time there. If you notice your betta doing this then there may be a problem.

  • Your betta could be floating at the surface of the tank due to a lack of oxygen in the water, or trouble getting oxygen from the surface.
  • It could also be due to swim bladder disease.

How To Treat?

  • If you think that it’s due to swim bladder disease then you should follow the advice given previously.
  • However, if it’s due to lack of oxygen then you should change 75% of the water and treat the new tap water with a water conditioner before adding it. You should also consider adding some live plants to your tank and make sure the filter system is working properly. And lastly, make sure there is enough space between the waters surface and the lid of your tank for your betta to breathe.

Why Is Your Betta Swimming Erratically After A Water Change?

If your betta is swimming erratically after a water change, then it could be due to the following reasons:

Temperature Change

If you’ve just changed the water in your betta’s tank then the temperature could have dropped or risen too much. When this is the case your betta may be going into temperature shock hence the erratic behavior!

If you notice that the temperature has dropped too much, you should slowly begin raising or lowering it until it reached the required level again.

The Water Wasn’t Treated

If you added new water to your tank, but you forgot to dechlorinate it first, then this could be the reason that your betta is swimming erratically. Water that hasn’t been treated is full of chlorine and other chemicals that are harmful to fish.

So if you think this is the case, add water de-chlorinator to your tank immediately!

The pH Has Changed

And lastly, another reason is that adding water to the tank has changed the pH. If this is the case. then it could be a problem with your tap water.

One of the best things you can do in this situation is add distilled water to your tank. Distilled water is neutral so it will bring the pH in the tank back to neutral. Before doing this though, make sure you’re testing the water first to be sure.


Is Erratic Swimming Always Negative?

Just because your betta is swimming erratically doesn’t ALWAYS mean there’s a problem. Sometimes your betta can be swimming erratically because they’re happy or exercising. As well as this, if he’s only swimming erratically when he sees you he could recognize he’s about to get food! So, the most important thing is to be AWARE of how your betta acts normally and carefully monitor him. And if something does go wrong you can give him the best possible treatment.


To recap, the most common causes of your betta fish swimming erratically are:

  • Swimming bladder disease
  • Parasites
  • Nervous system disorders & neurological damage
  • Poor vision
  • Hypoxia
  • Water quality
  • Nutrition

And when a fish is swimming erratically they often appear to:

  • Swim around in circles.
  • Float and stick to the surface of the water.
  • Twirl or swim in a corkscrew fashion.
  • Swim upside down.
  • Have troubles swimming to the top or sinking to the bottom.
  • Rub or bang into things.

Taking care of your Betta can be tricky, but with the right knowledge, it doesn’t have to be. Click here to read an article with everything you need to know about Betta fish care.

If you liked this article, make sure you check out the rest of the website! And if you have any more questions you can ask them in the Q&A Section!

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Helpful Articles

Swimming erratically can often be caused by diseases in your betta. And the earlier you catch the diseases the more likely the chances of your betta surviving. If you’re interested then here are some common diseases that affect bettas:

  • Fin Rot In Bettas – Fin rot is an extremely common disease and one that is easily treatable. However, if left too long fin rot quickly becomes fatal. That’s why it’s important to know how to spot fin rot, how to treat it and how to prevent it.
  • Dropsy In Bettas – You may have heard that once a fish has dropsy then they’re probably not going to survive. However, if you notice the early warning signs of dropsy you can decrease the likelihood of your betta dying.

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