Betta Popeye – Causes, Symptoms & Treatment

At first, it was just a slight white ring around his eye. But eventually, his eye began to swell. At this point I knew, my beautiful betta has popeye!

This led me to investigate what exactly this is, what causes it, and most importantly how to cure betta popeye!

What Is Popeye In Betta Fish?

Popeye is scientifically known as exophthalmia and is a disease that causes the eye of a fish to bulge out and appear cloudy or white. This can happen in just one eye or both simultaneously (unilateral or bilateral). 

This bulging is a result of swelling which occurs when fluid builds up in the space behind the eye. As the amount of fluid increases, pressure grows and this forces the eye to bulge out, giving the “popeye” look. 

Rose Petal Betta Fish With Popeye


What Causes Popeye?

What causes this fluid build-up? There are a few different potential causes. Most typically, a simple bacterial infection is what causes popeye in a betta fish. These bacterial infections are often the result of dirty aquarium water.

While less common popeye can be caused by a physical eye injury. Injuries can result from fighting with other fish, collisions with objects in the aquarium, or rough handling of the fish.

In rare cases, popeye can be caused by fish tuberculosis scientifically known as Mycobacteriosis. While this isn’t the same tuberculosis that humans get it is fatal and most likely incurable. 

Symptoms of Popeye In Betta Fish

How do you tell if your betta fish has popeye? As discussed above one or both eyes will noticeably bulge from the eye socket. 

Unilateral popeye where one eye protrudes is more likely the result of some type of injury. Bilateral, on the other hand, is a symptom of a more serious problem like a bacterial infection. 

In addition to the “popeye” symptom, your betta’s behavior will also likely change. The eye bulge is painful and causes vision problems and even blindness. Because of this, the betta may have trouble locating food.  

Other behavioral symptoms include lethargy and loss of appetite. You will notice this if you see him in his favorite hiding spot not moving around much for most of the day. 

Betta Fish Popeye Treatment

What can be done if your betta develops popeye? 

There are treatment options available depending upon the cause and severity of the popeye. If it is minor and caught early all that is needed are some basic treatments. More severe cases have been known to blind or even result in the eye decaying and falling off

Treating For Bacterial Infection

Step 1. Quarantine

The first thing you should do is move the betta to a quarantine tank. If your betta does not have any tank mates and you don’t have a proper quarantine tank it is fine to leave the betta in the tank. 

This not only gives you somewhere to treat your betta, but it also gives you the option to do a thorough cleaning of the main tank.  


Once your betta is isolated in the quarantine tank you need to treat its water. 

For mild cases, Epsom Salt on its own might do the trick. The salt aids in reducing the swelling and preventing further infection. The recommended dose is 1-3 teaspoons per 5 gallons of water. Salt is a good idea even if you opt for something stronger like an antibiotic. 

More severe cases of popeye will likely need antibiotic treatment. Depending upon who you ask you will hear a variety of different recommendations. As long as it is a broad-spectrum antibiotic intended for aquarium fish it should be sufficient. Two of the most effective are Ampicillin and Erythromycin. 

Make sure to follow the directions precisely when using these powerful antibiotics. 

Water Changes

A 100% water change of the main tank should be done at this time. Thoroughly clean the tank, decor, and equipment as well. 

Additionally, perform a 100% water change every 3 days in the quarantine tank as well. 

Return Betta to Display Tank

Once you have followed the protocol of your chosen medication regime and your betta is on the mend you may return him to the display tank. Continue to monitor your betta as well as the water quality with frequent water changes. 

Depending upon the severity it may take weeks or even months for the popeye to fully subside. 

Treating For Injury

Treating for popeye caused by injury is a simpler process than that for infection. 

Epsom Salt Baths

Epsom salt will help reduce the swelling and help prevent infection. To learn how to give your betta a salt bath watch this great video below!

Beyond Epsom salt baths all you need to do is follow the preventative measures explained below. These will help prevent your bettas injured eye from becoming infected. 

How To Prevent Betta Popeye

The best way to deal with betta popeye is to take steps to ensure it doesn’t happen in the first place!

There are a few things you can do to reduce the chances your betta has to deal with this painful situation. 

  • First and foremost, make sure your water stays clean. Do partial water changes once every week or two. Monitor your ammonia, nitrite, and nitrate levels. This will prevent bacteria and maintain your betta’s health. 


  • Don’t overstock your betta tank. The more animals you have the more waste that will be created. This means that your water will get dirtier faster. 


  • Prevent injuries. Make sure that nothing in your betta tank has sharp edges. Don’t use cheap plastic plants but instead opt for silk or live plants. If you handle your betta do so with the utmost care. If you have companion fish monitor them closely for aggressive behavior towards your betta. 

Final Thoughts

If you came here because your betta fish has popeye I wish you the best. Hopefully, the info you find here has helped you identify and successfully treat your betta’s condition!