How To Identify And Treat Popeye in Fish?

popeye in fish

The medical terminology used to describe Popeye disease is Exophthalmia. It is a condition in which the eye of a fish protrudes abnormally from its socket. This could be due to any other underlying condition. Popeye in fish can affect a single eye or both the eyes in fishes. Swollen and cloudy eyes also indicate that there is a problem in your aquarium fishes. You need to remember that your fish may lose its eyesight if not treated at the right time. Hence, you need to keep an eye on signs that seem abnormal.

To know more about different Saltwater and Freshwater Aquarium Fish Diseases, click this article “Aquarium Fish Diseases: Causes, Symptoms, and Treatments“.

Popeye Pathology in Fishes 

The swelling in the eyes of a fish is a result of leakage of tissue fluid in a region behind the eyeball. As the amount of fluid increases, there is a buildup in pressure. Further, this forces the eyeball of a fish outwards. Moreover, the buildup of fluid can also give rise to bacterial infections. The cloudiness noted in some instances is due to the damage caused to the cornea.  

Popeye in aquarium fishes results due to exposure to poor water conditions. You will find such cases in aquariums that receive infrequent water changes and also in crowded aquariums. Unhygienic conditions also give rise to Popeye disease. If you notice Popeye in fish, then you must act immediately to find the cause.  

Unilateral vs. Bilateral Popeye 

Bilateral Popeye in fish results due to reaction to poor water conditions in an aquarium. On the other hand, Unilateral Popeye in fish is due to physical damage faced by a fish. Regardless of the condition, it is crucial to optimize water quality if you want the fish to recover. Unilateral Popeye, however, will also demand further considerations. Physical damage may result due to collisions between fish, rough handling, aggression between fishes, and failed predation attempts.

Popeye in Fish Symptoms

You need to remember that certain fishes normally have telescoping eyes. If your fish breed doesn’t have telescoping eyes naturally, then it is high time to take some action. These are the signs commonly noted in fishes with Popeye. 

  • Swelling in one or both eyes 
  • Cloudy eyes
  • Rupturing of cornea
  • Signs of injury
Popeye in fish

What causes Popeye in Fish?

Multiple causative agents can result in Popeye in fishes. In certain cases, it is hard to determine the cause. If just one eye is affected, then it may be due to any injury rather than issues with water quality. A swollen eye may be due to a fight with another fish. Also, the fish may have come in contact with an abrasive object in the tank and would have scrapped its eye.

If you notice any abnormal sign, look for the kind of damage caused to the eye. As far as an injury is concerned, the protruding eye recedes once the injury heals. However, you need to monitor the fish closely and ensure that the condition is not due to an infection. If you neglect, then your fish may end up losing its sight.

If the protruding of eyes is due to an infection, then Popeye would be noted in both the eyes. Infection may occur due to a variety of microorganisms such as parasites, fungi, and bacteria. Internal problems such as kidney failure can also result in fluid buildup. In this situation, you will find it extremely difficult to treat your fish.  

Sensitive breeds are the first ones to get impacted due to poor water conditions. If you notice Popeye in one or more fishes in your aquarium or fish pond, then you must immediately determine the water quality in the tank. You should also suspect the supersaturation of gas in water to be the culprit. 

How to prevent Popeye in fish? 

There is no magic treatment for preventing Popeye. However, you can take certain measures to prevent its occurrence. You can take care of simple things such as maintaining the tank, feeding your nutritional fish food, changing the water in the tank regularly, focusing on hygiene, monitoring the health of your fishes periodically, and a lot more.

If basic care is taken, then Popeye is quite unlikely to occur. Maintaining water quality could also be the key to preventing the condition. Nitrate levels above 20 mg/l hint overfeeding, overstocking, or significant changes in the water quality of the aquarium tank. Avoid using abrasive or coarse fishnets to prevent damage to their eyelids. It is best to drive them into plastic containers instead of netting them. 

Some fishes tend to get nervous while under stress. They end up bumping into the walls of the aquarium or hit coarse objects in their attempt to hide. You must take special care while handling such species of fish. The simple act of turning on aquarium lights can cause nervous breeds to thrash or jump and injure themselves in the process. 

Make sure to turn on lights in dark rooms before switching on the aquarium lights. This will not have much impact on them as they would be used to the brighter lighting conditions. You should do the reverse at night. You should leave the room lights on after turning off the aquarium lights.    

Popeye disease can be prevented by simply providing a healthy environment to a fish. Taking care of the steps mentioned above will also minimize the risk of any physical damage, which can, in turn, prove disastrous.

Simple steps to consider for prevention of Popeye in fishes   

How to cure Popeye in fish?  

If you notice that your dear betta fish in your aquarium tank has developed Popeye, then you will have to act immediately to treat the condition. Treatment would be dependent on the underlying cause. If there is any injury to the eye, then you need to use aquarium salt and perform palliative care. This has to be done until the eye heals. Regular monitoring of water quality and frequent changes should also be done during the recovery period. 

If there is a problem with the water quality like elevated levels of nitrite and ammonia or if there are fluctuations in pH, then you will have to follow appropriate measures to control it. Also, make it a point to feed your fish high-quality food. This will ensure that they have a healthy immune system.  

If your fish is showing signs of bacterial infection, then you should immediately move it to a quarantine tank. Else, the other healthy fishes in the tank will end up getting infected. An infected fish should be fed antibiotic food that has been recommended by a veterinarian or a trusted pet supplier. If more than one fish has been infected, then you will have to treat the entire tank using antibiotics. If there is a parasitic infestation, then you will have to provide the appropriate treatment prescribed by a veterinarian. 

Difficulties in treating Popeye in fish

Many believe the popeye condition to be challenging to treat. This is because the condition poses various problems. The first thing is that there is damage to the cornea. Then there is an accumulation of fluid behind the eyeball of fish. Third, there is a chance of bacterial infection. 

Any minor damage can be treated over time. This is when the fish is being fed a nutrient-rich diet, and optimal water conditions are being maintained. The swelling will gradually rescind with time if you take proper care. Epsom salt helps with the swelling. Epsom salt for Popeye can work wonders. You should just follow the procedure appropriately. The usual dosage is 1-3 teaspoons for every 5 gallons. You can use Epsom salt in both saltwater and freshwater aquariums. However, treating Popeye in saltwater fish in quarantine tanks would prove to be the best.

Antibacterial medications and antibiotics can be used for preventing any damage to the cornea from a fully-blown popeye. Once the condition has fully developed, you will have to try different medications.  

Is Popeye in fish contagious? 

Popeye, in general, is not a contagious disease. You need to check the underlying condition. If Popeye is due to a bacterial infection, then the chances of other fishes in the aquarium developing the condition are quite high. Instead of neglecting, you should immediately find the cause and try to fix it. 

Popeye in freshwater fish is more of an outward sign that there is something wrong. For instance, Popeye could be due to ascites. Ascites is a condition in which there is an accumulation of body fluids in the abdominal cavity. This usually occurs when there is an issue with the kidneys. Popeye is sometimes manifested when there is a fungal infection in the body called Ichthyophonus hoferi. If Popeye results because of any disease, then the fish may succumb to the disease. Treating Popeye would not be beneficial in this case as there is some serious complication resulting in the eyeball being forced outward. Hence, diagnosis and treatment can play a crucial role in saving your pet fish. 

Melafix for Popeye in fish 

Melafix is a natural antibacterial medication that can prove to be beneficial while treating infections in fishes. It can work wonders in fishes would abrasions, open wounds, mouth fungus, eye cloud, and tail rot. It also promotes the regrowth of damaged tissues. You just need to add this medication into the aquarium. You should also use this while transferring your store-purchased fish into the aquarium. This will ensure a smooth transition and will heal infections if any.  

Melafix has no adverse effect on biological filters. It does not discolor water in your aquarium tank or alter the pH of water. You can use it in reef aquariums, saltwater, and freshwater aquariums as it is safe. Melafix causes no damage to aquarium tanks with live plants. You should follow the prescribed dosage mentioned on the label by the manufacturer. The recommended dosage is 5ml of liquid per 10 gallons of water. You need to dose for seven days and then change 25 of the total water in the tank.  

You can get rid of infections in your fishes by using Melafix. Popeye in saltwater fish can be treated with Melafix if the underlying cause for the condition is an infection. 


Popeye is a common condition that is noted in aquarium fishes. The cause may differ from one fish to another. Prevention is the best way to keep your fish safe from Popeye. If, by any chance, your fish is showing symptoms of Popeye, then make sure first to diagnose what is causing it. This will significantly help with the treatment. 

To know more about different Saltwater and Freshwater Aquarium Fish Diseases, click this article “Aquarium Fish Diseases: Causes, Symptoms, and Treatments“.