Popeye disease or Exophthalmos is not a disease. It is more indicative of underlying disorders. Popeye causes a build-up of fluids either behind the eye or in the eye itself, causing the eye to swell.

Injury, bacterial infection, or unhygienic quality water can cause Popeye.

Popeye can affect one or both eyes. It is easily recognizable because the fish’s eye protrudes from its socket. At times, the eye may look clear or appear cloudy. However, the eye may completely pop out of the socket in severe cases.

As a fishkeeper, you need to understand this disease and take steps to keep your pets safe. This article will explain popeye disease, its symptoms, causes, and treatment. Being prepared is vital to protect the other inhabitants in your tank.

Understanding Popeye Disease

Bulging eyes in a fish doesn’t necessarily mean there’s a problem. Some breeds, such as the Black Moor and Celestial Eye goldfish, are prized for their large telescoping eyes.

Popeye can affect both freshwater and saltwater fish. When only one eye is affected by popeye disease, it is known as unilateral Popeye. Bilateral Popeye is when both eyes are affected.

The severity of Popeye can range from mild to acute. In milder cases, the eye may stay clear, and the swelling will be moderate. However, in more acute instances, it damages the cornea, and the eyes cloud over.

If you do not take steps to remedy the problem right away, the swelling can worsen, and the eye will rupture and fall out. In addition, other health issues typically accompany Popeye disease. Since the fish’s immune system is weakened, opportunistic bacteria or fungal problems can lead to severe infections.

– Symptoms of Popeye Disease in Aquarium Fish

The early symptoms of popeye disease in fish are subtle, so it can be hard to detect the disease before it causes significant damage. Generally, the eye will only protrude slightly in the early stages. But soon, there will be considerable swelling that will also affect the skin around the eye.

Fish breeds that don’t have telescoping eyes can have a marked swelling of one or both eyes caused by fluid leaking into the area behind the eyeball. If the cornea is ruptured, the eye can be discolored. It can even be bloodstained if the fish is injured.

If the infection is severe and remains untreated, the infected eyes can rupture. While the fish may eventually recover, it will be blind in the affected eye.

You will also notice changes in the fish’s behavior. They may not be as active as before and may try to hide away from the other fish. They may also lose their appetite. Although the fish has lost weight, its body swells up.

Your fish looks as ill as they feel. The gills may become pale and eroded. Their scales start to stick out, and they develop ulcers on their body. They also have clamped fins and become lethargic. Their coloring may also change noticeably.

– How Serious Is Popeye Disease?

Popeye disease is a grave problem that must receive immediate care. The sooner you start to treat your fish, and the higher are the chances of recovery. Even though Popeye is not fatal, other complications could arise.

To begin, your fish could lose their vision in the affected eyes. If you do not treat the eye, they can decay and fall out. If your fish has unilateral popeye disease, they can still recover after losing sight in one eye, but it will impact their quality of life. Caring for the fish will be a challenge if they become blind.

Apart from the loss of vision, there are other concerns. Popeye can quickly lead to septicemia when the infection moves into the bloodstream. Most fatal cases of Popeye are due to septicemia as it can cause organ failure throughout the body. Your fish may also die due to parasitic infections or other potentially dangerous problems.

You will have to make some changes to help your fish. If your fish are carnivores or predators, they will need time to adapt to the loss of their eyesight. Meanwhile, peaceful fish will run the risk of being attacked by others in the tank.

– Common Causes of Popeye Disease in Fish

If your fish has Popeye disease, there are some possible causes you may need to consider.

Fish are prone to injury. Species that are either very active or timid are at a higher risk of getting injured. They could accidentally bump into tank decor such as rocks and scratch their eye on rough edges. Since they don’t have eyelids, fish cannot shut their eyes for safety in case of an accident.

Alternatively, your fish could also get into a clash with another fish in the aquarium. Maybe you could have accidentally hurt your fish with a net. Take a close look at the eye to be sure. Often, you can see signs of injury.

Often, Fish that are suffering from an infection get Popeye disease. Fish with weak immune systems are susceptible to the bacteria that can cause this disease.

Large Central and South American cichlids and large cyprinids like goldfish, carp, and koi tend to get Popeye. Stress is also a leading factor. Fish can get stressed by inappropriate transportation methods, fluctuations in water temperature, and an overcrowded aquarium.

Bilateral Popeye is generally the result of an unsuitable tank environment and nutritional deficiencies. Fish are not endangered by sudden drastic changes in water parameters but by continued exposure to unhygienic water conditions.

Popeye disease regularly causes trouble in tanks where regular maintenance tasks are not carried out. Constant exposure to high ammonia and nitrate levels and saturation of gases are also likely causes.

Although you may only find one fish with Popeye, you must act swiftly to prevent the other fish from succumbing to the disease.

Treatment of Popeye

The treatment of Popeye disease isn’t easy. You have to treat the underlying cause of the disease as well as potential bacterial infections.

These are the steps we suggest for treating popeye disease:

1. Test the water

Start by testing the water in the tank. If you can detect ammonia and nitrate levels, you need to address this problem right away. You must also make sure that the pH levels and temperature are within the acceptable range for your fish.

Perform daily water changes to safeguard the other fish in the tank; your tank needs thorough deep cleaning to eliminate waste and keep ammonia levels in check.

2. Quarantine the infected fish

Gently remove the infected fish from the main tank to isolate them. Please place them in a separate hospital or quarantine tank with optimal water conditions.

3. Use Epsom salts

You can treat the fish with Epsom salts to reduce swelling. Add one to three teaspoons of Epsom salt for every five gallons of water in the treatment tank.

The salts should reduce the swelling over the next several days. The corneal damage will also heal if you keep the water conditions stable. You must ensure that your fish is getting a balanced, vitamin-rich diet during treatment.

4. Tackle the bacterial infection

The next step is to deal with the bacteria, which can be tricky. You can use the standard antibiotic and antibacterial medication to fight off bacterial infections and stop the corneal damage from increasing.

These products, typically used to treat conditions like fin rot and other infections, are added to the water. For the internal infection, you will need to use a broad-spectrum antibiotic recommended by a vet. Since these come in the form of food, they are easy to administer orally.

The Prognosis for Popeye in Fish

A severe bout of Popeye may need treatment for several months. You must continue to monitor your fish and check the water conditions regularly. Eventually, the swelling will go down, and the eyes will go back to normal.

It would be a good idea to treat the main tank with an all-purpose antibiotic since the other fish in your aquarium could still be at risk. Improve the water quality and use an all-purpose antibiotic as a safety measure.

How to Prevent Your Fish From Getting Popeye

The most effective thing to do is adopt measures to prevent Popeye from happening. You must be proactive and take all potential causes into account.

Begin with your aquarium. If the nitrate level is more than 20 mg/l, it indicates overstocking, overfeeding, or insufficient water changes. If your tank is overcrowded, buy a larger one or find good homes for some of your pets. Your fish need ample space to swim around.

A larger tank is always better since the volume of water dilutes toxicity caused by waste. To prevent poor water conditions, check the parameters regularly. Change 20 percent water every week and ensure that your filter is working correctly.

Ideally, tests should not detect ammonia and nitrate levels. If the compounds are detectable, you might still have too many fish. Alternatively, you may need to replace your filter.

At feeding time, please give the fish as much food as they can eat in two minutes. It would be best to remove leftovers from the tank to keep the water clean and reduce the possibility of your fish getting Popeye.

The final step is the decor in your tank. While some rocks and driftwood are vital as hiding places for fish, they should not have sharp edges or be abrasive.

Fish eyes are easily damaged since they don’t have eyelids. Get rid of any coarse or abrasive fishnets. Use nets to guide your fish into plastic containers rather than netting them directly. Be very gentle when you clean the tank or move decorations around.


You can prevent Popeye simply by providing your fish with a wholesome environment. Take steps to minimize the risk of physical damage.

  • Popeye disease is a severe problem that you shouldn’t ignore.
  • Popeye disease in fish is dangerous, painful, and hard to fight.
  • Preventing popeye disease is relatively straightforward.
  • Adopt good care routines and keep a close watch on your fish.
  • Remove any decorations that can cause accidental damage
  • Maintain healthy water parameters.
  • You must take the necessary steps to keep your fish safe, healthy, and happy.
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