In general, bettas can live in smaller bodies of water than any other aquarium fish can tolerate. Nevertheless, even so, they need good care to maintain their health. Also, to avoid developing conditions common to ailing fish, such as popeye.

Thus, popeye also called exophthalmia causes pressure behind the eyeballs. Hence, it makes a fish’s eyes protrude. It’s much easier to prevent than to treat. Particularly, over time, betta eyes suffering from popeye can turn milky white and become damaged. Also, in severe cases, the eye or eyes can decay and fall out. Meanwhile

  • dirty water,
  • serious illness,
  • accidents,
  • mishandling and
  • fighting can cause popeye in bettas.


  • what is popeye?
  • what causes popeye?
  • causes of unilateral popeye
  • causes of bilateral popeye
  • popeye prognosis in fish
  • symptoms of popeye in bettas?
  • how to cure popeye in bettas
  • popeye caused by physical harm
  • popeye caused by infection
  • prevention of popeye in bettas
  • how to prevent infection
  • how to prevent physical harm
  • can betta fish die from popeye?
  • is popeye contagious?
  • summary

What Is Popeye?

In particular, Popeye is an affliction that affects all fish, not just bettas. Thus, its scientific name is exophthalmia. Specifically, Popeye is when pressure behind the eye causes the eye to protrude.

However, it’s a disease that’s easier to prevent rather than treat. But if you do not treat it, bettas often die.

What Causes Popeye?

Unfortunately, you can’t pinpoint what causes popeye to only one source. That is, there is a whole range of causes of Popeye. Meanwhile, if you don’t treat the correct one then the problem is only going to get worse.

Most common causes of Popeye

Causes of Unilateral Popeye

First, if you notice your fish has unilateral Popeye (if your fish has only one affected eye) then it may not be an infection of any kind. Meanwhile, in most cases, physical damage causes one eye swelling.

In particular, this can be a result of your fish

  • banging into something,
  • getting into a fight with another fish or
  • even if you’re too rough when catching him in a net.

However, if you house your betta in a tank with others and only he has unilateral Popeye, then it’s almost guaranteed to be the result of physical damage.

Causes of Bilateral Popeye

Generally, if you notice that your betta has Popeye in both of his eyes then it’s almost certainly an infection of some kind. Thus, the infection can be caused by

  • parasites,
  • fungus or
  • bacteria.

Popeye Prognosis in Betta Fish

In general, given prompt treatment and good environmental conditions, popeye can get better with time. Particularly, it takes weeks or months for the swelling to diminish.

Also, the damage to the cornea of the fish can be even slower to heal.

However, severe damage to the betta fish’s eye may never heal completely. It never heals even if the swelling itself goes down.

Meanwhile, in extreme cases, the betta fish’s eye may be so badly damaged it

  • decays, and
  • falls off the fish.

Generally, blindness in one eye does not seem to incapacitate fish unduly. However, carnivorous fish that hunt by sight may find the loss difficult to get used to.

Thus, keep such fish away from boisterous competitors. Also, use forceps to hand-feed them if they have trouble feeding themselves.

Likewise, because negative environmental aquarium factors usually cause Popeye, fish suffering from popeye will often be stressed or diseased in other ways.

Meanwhile, while popeye itself isn’t likely to kill a betta fish, affected fish could die from other problems, such as

  • septicemia and
  • Hexamita infections.

What are the Symptoms of Popeye in Betta Fish?

If your betta fish is suffering from Popeye there is more than one symptom apart from the most obvious.

Eyes Popping Out

In general, the most obvious symptom of Popeye is one or both eyes popping out. In fact, when you see this symptom you can know that your betta is suffering from Popeye.

Again, it can be one eye that’s popping out or both. Thus, you’ll have to treat each case accordingly.

Eyes Changed Colour

On the other hand, apart from eyes popping out, your betta’s eyes may also change color. Particularly, they could look cloudy or milky. However, it could also look bloodstained.

Also, a bloodstained eye is most commonly associated with physical aggression.

A White Ring around your Betta’s Eyes

Often, this is something to look for early on. That is, if you spot it you may be able to treat Popeye before it causes your bettas eye to pop out.

Thus, if you do notice a white ring around your betta’s eye then you should start treating it for Popeye

Other Signs of Illness

Likewise, your betta will showcase some of the typical signs of illness when his Popeye is an infection. Hence, you’ll notice a lack of energy as well as a loss of appetite.

Likewise, he may seem to stay in one place more often and try to avoid other fish as well.

How to Cure Popeye In Bettas

If your betta fish is suffering from Popeye then you’re going to have to treat it depending on the circumstances. Thus, the way you treat Popeye caused by physical harm is different from Popeye caused by an illness.

Popeye Caused by Physical Harm

Generally, if you think that Popeye is the result of physical harm, then there’s not as much you can do. However, the good news is that this kind of Popeye is less likely to be fatal. This is because your betta isn’t in a dangerous environment.

Hence, here are the steps you should take:

  • First, remove 10% of the water from your tank and place it into a container.
  • Next, add your betta to the container and dose it with Epsom salt. Meanwhile, there will be a recommended amount on the bottle. Also, there will be some instructions on how to use it. However, just remember, that you should dissolve Epsom salt before adding it to the container.
  • Also, you should leave your betta in the container for 10 minutes before adding it back to your main tank.
  • Next, make sure you float the container in your aquarium to keep the water warm enough.
  • Alternatively, you can likewise add aquarium salt to your betta’s tank. Particularly, this is going to improve your bettas immune system. Also, it will help him recover faster.

However, if you’re adding salt you should be changing your water more often.

Popeye Caused By Infection

In contrast, if your betta fish is suffering from Popeye due to infection then the method of treatment is going to be different.

Thus, the first thing you’ll need to do is move your betta to a quarantine tank.

Meanwhile, once you moved your betta from your main tank. Then you should also perform a 100% water change. Usually, this is going to help reduce the chance of other fish getting infected.

Likewise, begin treating your betta with ampicillin and aquarium salt. Thus, you should use 1 capsule of ampicillin for every 10 gallons of water.

However, make sure you premix the ampicillin with a small amount of aquarium water before adding it to your tank. Meanwhile, if you’re unsure about dosages you should ask a professional.

Also, remember that different medications will require different dosages.

Likewise, perform a 100% water change every 3 days and

  • add ampicillin and
  • aquarium salts.

However, make sure you don’t use ampicillin for more than 10 days. Thus, once you’re through dosing your betta, change the water one more time. And then leave your betta until you feel he’s on the mend.

Therefore, remember Popeye can take months before the eyes return to normal.

How to Prevent Popeye in Betta Fish

Generally, the best way to stop your betta suffering from Popeye is preventing it altogether. Thus, to do this, you should try to prevent the two main causes of

  • physical damage, and
  • infection.

Similarly, there are a number of ways you can do this.

Stable Temperatures

In particular, a steady temperature within the aquarium reduces the risk of your betta developing popeye. Also, bettas need warm, stable temperatures between 72 and 82 degrees Fahrenheit.

Often, rapid temperature changes weaken their immune systems. Thus, don’t allow a betta tank’s temperature to drop below 70 degrees Fahrenheit.

Alternatively, change more than three to five degrees within 24 hours.
Also, you should fit tanks larger than 5 gallons with aquarium heaters.

A Safe Environment

Generally, a safe environment reduces the risk of popeye caused by injury. Thus, don’t use coarse fishnets to handle a betta. Also, use a net to guide the fish into a plastic container to remove him from the tank.

Furthermore, turn on room lights before turning on aquarium lights to avoid startling a betta. Also, don’t keep a male betta with other male or female betta, to avoid fighting.

How To Prevent Infection

Clean Water

Often, maintaining clean water helps prevent popeye in betta fish. Usually, bettas can survive in small containers of water. This is because they can take in air at the water’s surface. However, they need frequent water changes to maintain good water quality.

Thus, change 100 percent of the water every day in tanks smaller than 1 gallon. Also, change 25 percent of the water every week in larger tanks. Therefore, to complete a 100 percent water change, guide the betta into a small container of his current aquarium water. And then scoop or siphon out all the remaining water in the betta tank.

Also, refill the tank with freshwater, and replace the betta. Likewise, always refill your betta’s tank with treated water to remove

  • chlorine and
  • other chemicals.

Similarly, vacuum or siphon the gravel at every water change.

Again, if you’re trying to prevent infection then you’re going to have to focus primarily on improving the water quality of your tank. Poor water quality is going to affect the immune system of your betta fish. Also, it will so much stress them out.

Thus, some of the main ways you can improve water quality are:

  • First, ensure to not overstock your aquarium. Often, if there are too many animals in your tank, then your filter is going to have trouble cleaning the water quick enough. Thus, remember everything in your tank is going to have a bioload. Meanwhile, if the bioload increases quicker than your filter can remove it, then the water quality will start dropping.
  • Also, if you notice any other fish in your tank have an illness then remove them from the tank. And then move them to a quarantine tank instead.

How to Prevent Physical Harm

Similarly, you should try to limit the amount of physical harm caused to your betta.

Here are some of the things you’ll need to watch out for.

  • First, ensure you don’t have plastic plants in your tank. Generally, plastic plants are too harsh on bettas. Also, it can cause damage to their whole body, including their eyes. Thus, if you have plastic plants you should substitute them for real or silk ones.
  • Next, be careful when you plan on handling your betta fish. If you need to scoop them up, take the extra time to make sure you do it with so much care. Otherwise, you could actually damage their eyes with the net.
  • Also, if you notice any other aggressive fish in your tank, then you should move them to another tank. Even if you see the breed as peaceful, there’s always an exception to the rule. Likewise, you should look out for any fin nipping or aggressive behavior
  • Lastly, ensure to not turn your aquarium lights on too quickly. Particularly, this can cause your betta to become stressed and swim frantically. Instead, you should turn the light in your room on for a bit. Meanwhile, after 10 minutes turn your aquarium light on. Doing this replicates sunrise much better than a sudden change in lighting.

Betta Care

In general, providing good care for betta fish suffering from popeye helps prevent the condition from returning. Particularly, add plastic or live aquarium plants to your betta’s tank to

  • reduce stress, and
  • feed carefully.


  • overfeeding, and
  • poor diet contribute to ill health in betta fish.

Thus, feed young betta twice a day or an adult once a day. Also, give as much food as the fish can eat in two to five minutes. You should try to vary the diet.

Aquarium stores sell specialized betta fish food. Meanwhile, you should supplement this with

  • freeze-dried brine shrimp, and
  • bloodworm


  • frozen and live small crustaceans,
  • worms and
  • insect larvae also provide variety in a betta’s diet.

Thus, one day per week, don’t feed your betta. This is to allow his digestive system to clean itself out.

Can Bettas Die from Popeye?

In general, if a betta has Popeye it’s quite hard for them to die from the ailment alone. In fact, it’s common for the eyes to become so damaged that they rot off. And the betta fish still survives.

Meanwhile, if this happens, it can be harder to feed them. Nevertheless, in general, they can still live.

However, what bettas will die from are the conditions that cause Popeye. Particularly, if your betta is in bad water and already has Popeye, then it’s likely to get other illnesses as well.

Also, infections that cause dropsy are more likely to infect your fish as well.
Thus, while Popeye itself is quite unlikely to kill your betta, the infections that follow if you do nothing aren’t.

Is Popeye Contagious?

Just like the last question Popeye itself is not directly contagious. Thus, if you took betta with Popeye out of your tank and moved it to a tank with great water conditions it’s very unlikely any other fish would catch Popeye.

However, if one fish in your tank gets Popeye then the others are more likely to get. Because infections that cause Popeye need poor water conditions to flourish. Therefore, while Popeye isn’t contagious, it will infect other fish in the same poor water conditions.


Just to recap, the good news is that if your betta fish has Popeye, then he still has a good fighting chance. Nevertheless, you are going to have to make some changes to make sure he lives.

Thus, here are the most important things to remember.

  • First, Popeye is when your bettas’ eyes protrude from their faces.
  • Also, it can be caused by physical damage or infections.
  • If it only occurs in one eye, then it’s most likely caused by an injury. However, if it’s in both eyes, then it’s most likely caused by infection
  • Also, you have to base your treatment on whether it’s due to physical injury or infection.
  • To prevent Popeye make sure you eliminate anything that can cause physical damage to your betta fish. Or if it’s caused by infection make sure you keep the water conditions in your betta tank excellent.
  • Also, it’s uncommon for bettas to die from Popeye. However, if it’s caused by bad water conditions, something else is more likely to harm them.
  • Lastly, Popeye isn’t contagious. Nevertheless, if it’s caused by an infection then the water conditions that cause it are probably doing damage to your other fish as well