You’ve probably seen a betta fish with a sunken or swollen eye. It may even have made their eyesight quite poor. As it turns out, there are treatments you can use to rehabilitate a betta fish with popeye disease. Betta fish popeye is quite common with its causes, symptoms, and treatments dealt with below.

Betta fish popeye is a condition in which the fish’s eye(s) appear to be swollen or bulging from injury, infections, tumors, or foreign objects in the eyes. Betta fish eyes are treated with aquarium salt, Epsom salt, chloramphenicol ointment, milk thistle, medication, and changing the water.

What is Popeye in Fish?

Popeye, also called exophthalmia, is a condition in fish that causes the eye to protrude from the socket. It is caused by a bacterial infection, which can be either external or internal in origin. The infection can go from one eye to the other, so it’s important to treat both eyes at once.

When you compare normal betta eyes vs popeye, you can easily see that the condition makes the eyes of the fish swollen or red in color and they generally appear injured. However, not all betta swollen eye conditions are popeye. To be safe when you see a betta fish eye pop, always consult your vet.

What Causes Betta Fish Popeye?

This condition is relatively easy to spot because it’s very noticeable: it looks like there’s a bubble in the fish’s eye. This condition can also cause swelling or cloudy patches on the eyeball.

There are many potential causes of popeye in bettas. However, popeye is a symptom and not a disease. Therefore, determining the root cause is important to treat it.

Unilateral vs. Bilateral Popeye

Popeye can occur only in one eye (unilateral) or both eyes (bilateral). While the two conditions may appear similar to the untrained eye, treatment may differ depending on which type of Popeye your betta has.

Unilateral popeye

Unilateral Popeye most likely has an external cause since one eye is affected rather than both of them. The causes include:

  • Injury: If you bump your betta’s tank or change your betta’s water without properly acclimating, you can injure the swim bladder and cause popeye in one eye. A common sign that this has occurred is if your betta swims with his head tilted slightly. It can also occur due to injury from another fish. While some fish may bully bettas, placing bettas and platies together can lead to the latter being bullied instead.
  • Foreign Object: If your betta is stressed, he may rub his head against the side of his tank or on any substrate sharp enough to scratch his eye. If a piece of gravel scratches his lens, it may cause popeye.
  • Bacterial Infection: Your betta’s water should be kept clean at all times, but it may become contaminated with bacteria that can infect the eye.

There are many other causes of this condition but these ones are the most common ones. 

Bilateral popeye

There are several causes of bilateral popeye in betta fish. This is when both eyes bulge. The betta fish bulging eye may be barely noticeable or severe. Some of the causes of bilateral popeye include the following:

  • Bacterial infections such as those caused by Aeromonas and Pseudomonas, are the most common cause of bilateral popeye. These bacteria are often found in dirty water conditions and in live foods.
  • Fungal infections can also cause bilateral popeye in betta fish. Fungal infections can be treated with medication and clean water conditions.
  • Parasitic infections are the third reason for bilateral popeye in betta fish. Such parasites include Trichodina and Ichthyophthirius multifiliis (Ich). Treatment for the parasite depends on what the parasite is and how severe the infection is.
  • Tumors can also cause bilateral popeye in betta fish.

Bilateral popeye is dangerous since it can significantly affect the vision of the fish. As such, it needs quick intervention each time you see both betta eyes popping out.

Symptoms of Popeye in Betta Fish

Popeye can be difficult to diagnose because there are many different causes. If your betta has this condition, he will have bulging eyes and may look as if he has been crying. A healthy betta should have a lean, streamlined body and clear, protruding eyes.

If you notice any of these symptoms, it could mean your pet is experiencing popeye:

Normal eyesPopeye
Flat Popped eye(s)
Clear Eyes have a milky/cloudy/opaque look
Clear or with tiny blood vesselsEyes are bloodshot
Clear area around the eyeWhite ring around the eye
  • Sunken eyes that appear cloudy or sunken into the head. This may be accompanied by redness or swelling around the eye socket. 
  • Bulging eyes that look like they are popping out of their sockets.
  • A swollen face or cheeks which may be accompanied by an inability to close the mouth properly due to the swollen tissue around the mouth area.
  • White ring around the affected eye(s). This symptom occurs early on when the popeye is about to set in and can be used to treat it early.
  • Abnormal swimming such as swimming at a tilted angle. At times, the fish doesn’t swim at all.
  • Not feeding or showing interest in food.
  • The fish may not come to the surface for air as often as it usually does.
  • The fish may hide from its tank mates. This is a sign of stress.
  • Your betta may also be spending too much time at the lower levels of the tank rather than at all levels.

If you’re keen on your bettas, you’ll easily see these signs once they manifest. 

How to Treat Popeye in Betta Fish

Popeye is a common disease that various methods can easily treat. First, do not panic if you think your fish has popeye. As long as you treat it quickly, your betta fish should be fine. 

Try the following remedies:

1. Try aquarium salt

Aquarium salt is a common treatment for popeye in fish. It helps to reduce the swelling and inflammation of the eye. The salt will also help to keep your betta’s water at the correct pH level. 

You should use aquarium salt that contains iodine or potassium iodide as these are essential for healthy gills. However, if you use a product that does not contain these ingredients, add some aquarium salt with iodine or potassium iodide to it before use.

If you do not have any aquarium salt in stock, you can use table salt instead but make sure that it does not contain any additives such as anti-caking agents or flavorings as they may be toxic to your fish.

Aquarium salt is a bit harsh on fish. For this reason, you’ll need to only keep the fish in it for a period of 5 to 8 minutes. This calls for a hospital or quarantine aquarium for such cases.

2. Use Epsom Salt

This method may seem odd, but it is actually very effective. Epsom salts can be found in most grocery stores and health food stores. The brand name doesn’t matter. 

It is often used as a laxative and can be found in the health section of your local grocery store or pharmacy. Add ¼ teaspoon to 1 gallon (3.7 L) of water and stir well to dissolve it. 

Add this solution to the fish’s tank and leave it for about half an hour, after which you should do a full water change with fresh water. Repeat this process daily until symptoms improve, then stop.

3. Use Chloramphenicol Ointment

Use chloramphenicol ointment (available at pet stores) on the infected area. This ointment is designed for use in the eyes and is safe for fish.

Use a clean cotton swab to apply a thin layer over each affected eye. After that, place your fish in a separate tank for 2 weeks until the infection clears up completely.

You may also want to consider treating the water that your fish is swimming in with antibiotics. However, this method might not be ideal because it will be harder to keep track of how much medicine your fish is getting and how long it has been getting it. 

If you do choose this method, make sure that you are following the instructions on the package exactly and that you are continuing treatment until symptoms subside (usually about two weeks).

4. Change The Water 

Change all of the water (or at least 90% of it) in your tank and make sure that it is clean and free of debris and harmful bacteria. You should also ensure that there is proper aeration in your tank so that harmful bacteria do not grow while you treat your pet with antibiotics.

5. Treat with Milk Thistle Extract 

This home remedy can be used for cases of physical trauma where there is no infection present. In addition, the milk thistle extract contains silymarin which helps regenerate damaged liver cells in fish. This can help reduce swelling and inflammation around damaged tissue in your betta’s body.

6. Medication 

A veterinarian may prescribe antibiotics such as tetracycline hydrochloride, Kanamycin, Erythromycin, and Melafix if an infection or injury causes the popeye.

Knowing how to treat betta fish swollen eye goes a long way in keeping the fish healthy and avoiding further complications. If you can’t carry out any of the methods above, consult a vet.

How long does betta fish popeye take to heal?

Betta fish popeye can take from a few weeks to a month to heal and the eyes to go back to their normal look. Once the fish returns to its normal behavior even when the eyes are still popping, you should stop worrying as the eyes will go back to normal in no time.

Can Popeye Kill Beta Fish?

Popeye can kill betta fish if not remedied early enough. This disease is not always fatal, but if left untreated, it can lead to blindness, secondary bacterial infections, and even death in some cases.

Luckily, when the right treatment is given, the seemingly dead betta will come back to life. Always consult a vet if the remedies you’ve tried so far aren’t working.

Is Betta Fish Popeye Contagious?

Popeye in betta fish is not contagious. Popeye can be caused by a number of different things, including infection, trauma, nutritional deficiency, and more. However, if it’s due to a bacterial infection in the water, it can spread to other fishes or marine pets in the tank.

If you think your fish might have popeye, you should take him to the vet immediately. The sooner treatment begins, the better the outcome for your fish.

How to Prevent Betta Fish Popeye

Keep your bettas free of popeye with the following methods:

  • Do not overfeed your betta. Make sure that you feed it only what it needs and no more. If you feed your betta too much, the immune system will not be strong enough to fight off the diseases and other conditions that cause it.
  • Keep your betta in a clean environment. Clean your tank at least once every week by removing any uneaten food and feces from the bottom of the tank. You can use aquarium salt or water conditioner to help remove any harmful bacteria from your tank as well.
  • Increase the temperature of your tank water to 82 degrees Fahrenheit during the treatment of popeye and add carbon dioxide to increase oxygen levels in the water.
  • Make sure that your tank is not overcrowded so that there are enough oxygen levels in it.
  • Treat your water with an anti-chlorine solution to remove chlorine and other harmful chemicals from your betta fish.
  • Replace sharp toys or plastic plants with live ones to avoid injuries. There are many good plants for bettas to choose from.
  • Ensure the betta affected by popeye isn’t being bullied by others. This may require separating the fish into different tanks. Between species, you can place bettas and goldfish together but other combinations may not work.
  • When moving the fish around, use cups instead of nets as they are delicate fish that cna easily get hurt by the nets.
  • You should also avoid making sudden changes to the fish tank. For example, don’t drop in objects suddenly or turn on the lights abruptly. The fish may get startled and hurt itself leading to popeye or ripped fins.
  • Avoid filters with strong currents as bettas aren’t strong swimmers. They may be injured with the strong current from a filter for example.

These routines and tips should reduce the likelihood of your pet fish getting popeye. 

Prevention is Better than Cure

If you’ve ever owned a betta, chances are you’ve dealt with popeye at some point. Popeye can be a scary diagnosis for any new fish keeper, but it’s important to learn how to recognize and treat it.

Bettas are particularly susceptible to popeye because they come from shallow rice paddies that are low in oxygen and nutrients. They’re used to adapting to their environment in the wild, but that also means they’re prone to bacterial infections when they don’t have access to proper nutrition.

Luckily, popeye is easy to prevent and treat if you know what you’re doing.


University of Connecticut. AquaLife Club- Get Your Fish On! Plus tips for keeping your pet Betta happy and healthy.


University of Wisconsin. Examining regeneration through a fish’s eye.

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *