Cloudy Eye Fish: Causes, Signs & Treatment

Cloudy eye fish is a common disorder in fish that creates a white film appearance on the eye. It is caused by a number of factors, including poor water quality, injury, and bacterial or viral infections.

In most cases, it is treated successfully with antibiotics or other medications.

You should carefully monitor its condition and take steps to improve its environment if necessary. However, if left untreated for too long then mortality may occur.

The following content discusses the major causes of cloudy eyes and how to cure fish cloudy eyes.

Cloudy Eye Fish
Image: Cloudy eye fish

What Is Cloudy Eye Fish Disease

The cloudy eye is a common and often fatal disease of marine and freshwater fish.

This is caused by the accumulation of mucus and other secretions in the eyes of fish. The cloudy eye results in difficulty seeing.

It is caused by gram-negative bacteria streptococcus or related bacterium and typically affects fish that are stressed or injured.

The disease can cause the eyes of the fish to become cloudy, inflamed, and sunken.

The disease-causing bacteria can be introduced into the water by a variety of means, including contaminated food, water changes, and handling of sick or dead fish.

It is most commonly seen in saltwater fish, such as marine angelfish, reef fish, and aquarium fishes.

The problem can be treated with antibiotics or anti-parasitic medications, but it is often difficult to cure and the fish may eventually need to be euthanized.

Causes of Fish Cloudy Eye Disease

The disease in fish can be caused by a number of things. It is important for hobbyists and pet store employees to be able to identify the cause in order to provide the best possible care for the affected fish.

There are many possible causes of disorder in the eye of finfish. Some of the most common causes include poor water quality, bacterial infection, or parasitic infection.

Some of the major reasons are,

1. Bacterial Infection

The dominant cause is bacterial infections and inflammation. If you notice just one milky sheen in their pupil and it does not clear up on its own within a week or two then this could be an indication of bacterial infections developing in the cornea layer at the surface of your pet’s eyeball.

Streptococcus bacteria is a major cause of cloudy eyes in fish. The bacterium can cause severe eye infections in both freshwater and saltwater fish.

Symptoms of streptococcus infection include watery eyes, redness, inflammation, and scarring.

If untreated, the infection can lead to blindness. Some of these causes can be treated with antibiotics or anti-inflammatory medications.

2. Poor Water Environment

Many fish owners are unaware of the fact that poor water quality but its another major cause.

In fact, this problem often crops up when tanks aren’t cleaned or filtered regularly, or when there’s an imbalance in the tank’s pH levels.

Poor water quality can be caused by a number of things, including high levels of nitrates and ammonia, low oxygen levels, and lowered fish immune system.

All of these factors can irritate the fish’s eyes and lead to the development of a cloudy appearance. It is a common sign of chronic stress caused by bad water.

3. Parasitic Infestation

Another possible cause is a parasitic infection. The causing parasite is called Ichthyophthirius multifiliis, often shortened to Ich.

These protozoan parasites invade through open wounds where they release their own digestive enzymes which eventually caused eye clouds.

Ich is a type of ciliated protozoan that lives in water and infects fish.

It can cause inflammation and damage to the tissues of the eye, leading to cloudy eyes.

4. Physical Injury

Injuries are one of the leading causes of eye disorder.

Fish can sustain injuries from a variety of sources, including fighting with other fish, being handled by humans, and being struck by objects.

Injuries can cause physical damage to the eye that leads to inflammation and cloudiness.

Fish with this problem face difficulty in seeing, which can lead to further injuries.

A study observed that when fish were injured, their eyes became cloudy, which inhibited their vision.

5. Imbalance Diet

If an aquarium or cultured fish diet becomes more limited or unbalanced because of finicky eating habits, it can lead to issues with cloudy eyes that are both painful for them and an inconvenience in cleaning up after a water change.

If your fish is a finicky eater, it may be time to try out some new brands or spice things up with different flavors.

Remember that just as there are foods we can’t live without; maybe our pet fishes have one brand of food they cannot resist.

6. Lower Immunity

A study has found that lower fish immunity can cause eye cloudiness in fish. A lowered immune system can make your eyes a little cloudy, or even full of slime.

This is because the immune system of these fish relies on their legs to fight off infections. When lower body immunity is impaired, the fish are more likely to get sick and have cloudy eyes as a result.

By understanding fish immunity and its disturbing factors, farmers can begin to improve their conditions to prevent these diseases from occurring.

This is usually due to an infection and the most common cause of this type of inflammation is bacteria that comes from neglecting regular tank maintenance.

7. Overcrowding

Overcrowding is a sign of poor water quality. High stocking densities reduce the water’s ability to support healthy aquatic ecosystems, which can cause disease.

This overcrowding also makes it harder for fish to find food and space, compromising their health and well-being.

In general, crowded conditions lead to an increase in the number of parasites, bacteria, and fungi that can cause diseases in fish.

Overcrowded conditions also lead to stress on the fish, which can induce them to develop the disease.

8. Tumor Cells

Tumor cells have been observed in the eyes of some fish, and this has led to the hypothesis that these cells are responsible for developing cloudy eyes in these animals.

The tumors can form anywhere in the fish’s body but are most commonly found in the internal organs and skin.

Tumor cells have also been found in the livers, spleens, and other organs of these fish.

The tumors may also grow on the inside of the fish’s eyeball, blocking the eye’s normal flow of fluids and causing it to become cloudy.

The tumor may eventually cause blindness if not treated.

Researchers are currently working to identify what causes these tumor cells to develop and spread, and hopefully, this information will lead to new ways of preventing or treating eye diseases in fish.

For example, Parasitic tumor cells, usually grow benignly on the skin or fins of a koi but can sometimes inhabit their eyes and cause blindness.

9. Genetics

There are a couple of fish species that have naturally milky or opaque-looking eyes and these can’t just always go by the appearance alone because there is no way to tell if they’re sick unless you do some research on them specifically. 

For example, goldfish with cloudy eyes usually don’t mean anything bad while other varieties may need more attention paid.

Species like pufferfish and rabbitfishes will have a white sheen in both irises when healthy-looking whereas another type might only ever show one eye as such so it’s important.

Signs & Symptoms of Cloudy Eye Fish

The signs and symptoms of cloudy eye fish can be difficult to diagnose, as they can mimic many other problems.

In general, however, there are a few key things to look for if you suspect that your fish may have cloudy eyes.

-One of the most common signs of cloudy eye fish is when the eyes appear cloudy, milky, or foggy.

The fish may have trouble seeing well and may not be able to locate food, shelter, or predators.

-This can be accompanied by other symptoms such as lethargy, loss of appetite, and abnormal swimming patterns.

-The scales on the fish’s body may also take on a grayish hue.

-Changes in their behavior will be observed, including an increased tendency to swim near the surface of the water and a decrease in their appetites.

a Opaque or cloudy eye
Image: Cloudy eye fish picture; Source: Researchgate

Diagnosis Cloudy Eye Fish Disease

When it comes to fish, one of the most common eye problems is cloudy eyes. It is a condition in which the eyes are covered by a thin film, which makes it difficult for the fish to see.

In most cases, the cause can be determined by performing a physical examination and taking a sample of the water for testing.

If the cause of the disease is not obvious, then additional tests may be necessary to determine the causes as the treatment will vary depending on the underlying cause.

This disease can be either one or both, but cloudy eyes usually only happen if there is another illness occurring first.

If you notice one clouded-over cornea and no other symptoms such as redness or discharge from that area then it is likely due to an abrasion with minor pain associated with rubbing against gravel or rocks while swimming around.

When examining your fish for cloudy eyes there are two important things to look at:

  • The size of the cloudiness on either eye
  • The shape of that blood vessel running through the eyeball (iris)

Prevention of Fish Cloudy Eye

First and foremost, it is important to establish the diagnosis of the cause of the eye cloudiness.

Once this has been done, it is then possible to determine the appropriate dosage of antibiotic required.

It is also important to keep in mind that fish can develop resistance to certain antibiotics if they are over-used or improperly administered.

So, prevention is important to maintain good fish health. Follow these tips to help keep your aquarium clean and healthy:

-Feed a high-quality diet that is balanced and includes plenty of fresh vegetables and fruits.

Keep the water clean by regularly cleaning the tanks and filters.

-Use proper sanitation measures such as keeping the tank clean and disinfecting it on a regular basis.

Avoid overfeeding or overcrowding your fish, as this can lead to unhealthy conditions.

Provide enough light for your fish, including using a fluorescent light during the day if desired.

Keep your fish warm and calm during cold weather, which can help reduce cloudiness in their eyes.

-In order to prevent cloudy eyes, you should try to keep your fish well-groomed and free from excess shedding.

Cloudy Eye Fish Treatment | Fish Cloudy Eye Medication

1. Remove Dirt or Debris From Eye

The first is to remove any dirt or debris from the eyes with a Q-tip or cotton ball.

Gently clean the eyes until they are free of any discharge.

Use tap water or clean water flash to remove the dirt and move to the hospital tank for further care.

2. Antibiotic Treatment

Treatment depends on the cause of the problem. If the cloudy eye is caused by an infection, antibiotics may be prescribed.

If it is caused by parasites, antiparasitic medications may be prescribed to kill the parasites.

There are many different types of antibiotics and each one can have different effects on fish.

Some antibiotics are effective at treating cloudy eye conditions, while others may not be as effective.

It is important to choose the right antibiotic for the treatment of your fish’s cloudy eye condition.

The dosage will also vary depending on the type of antibiotic and the age of your fish.

Always follow the instructions that come with the medication to ensure success.

Fish owners are often concerned about the antibiotic treatment for a cloudy eye problems, especially when it comes to treating their fish in a home setting.

However, there is no need to be overly concerned about the use of antibiotics for this purpose.

In fact, it is important to take a careful and precise approach and dose when administering antibiotics.

3. Salt Treatment

Salt treatment is a common way to treat cloudy eye problems in fish.

Some tips for salt treatment include:

Start with a very low dose, usually just enough to cover the water surface.

Wait 30 minutes before adding more salt, to allow the first dose to work its magic.

Do not overdose, as this could be harmful to your fish.

Monitor your fish’s health regularly while they are undergoing salt treatment, and increase or decrease the dosage as needed.

4. Improve Water Quality

Water quality can play a significant role in the treatment of cloudy eye problems in fish.

Properly maintaining water quality can help to reduce the number of pollutants that enter the system and can ultimately improve the overall health of your aquarium inhabitants.

Make sure to clean your tank and filter regularly, and test your pH, ammonia, nitrite and nitrate levels to ensure they’re in balance. Use quality water test kit that provide the accurate test result of different water parameters. If necessary, adjust them using a pH balancer available at most pet stores.

After test if the test results show that the water parameters fall outside the ideal range, remedial actions may be necessary to enhance water quality.

Suppose the pH level exceeds or falls short of the recommended range, adding pH adjusters can help to bring it back within the appropriate range.

If ammonia, nitrite, or nitrate levels surpass the recommended levels, options such as water changes, introducing beneficial bacteria or using suitable water treatments may be necessary to lower the levels.

Here are some tips for improving water quality:

-Make sure to remove all debris, including plant material and organic matter, every day. This will help to reduce the number of bacteria and other contaminants that can build up over time.

-Another important step is to add nutrients regularly. A balanced diet for your fish will include both food and fertilizers.

-Fertilizers help promote vigorous growth and healthy aquatic ecosystems, while food provides essential nutrients needed by fishes.

-Finally, make sure you adjust your water temperature as necessary.

5. Provide Balanced Diet

Provide a properly balanced diet. If the fish’s eyes do not improve within a few days, take it to a veterinarian for additional treatment.

Identify any potential dietary issues and make the appropriate adjustments.

Vitamin deficiencies are also a common cause of this issue in tropical fishes.

6. Surgery

If poor water quality is the cause, steps should be taken to improve the water quality. In some cases, surgery may also be necessary to correct the problem.

Fish Cloudy Eye vs Fish Popeye

Fish cloudy eye and fish Popeye are both common diseases that can affect the fish eyes.

The fish cloudy eye is a condition that causes the eyes of a fish to become cloudy or opaque. The cause of this condition includes a variety of factors, including infection, poor water quality, and exposure to chemicals.

Fish Popeye is a condition that causes the eyes of a fish to become swollen and protrude from the head. The major reason behind the condition is microbial infection and physical injury.

Although these two conditions are similar in some ways, they are also different in many ways.

For example, the symptoms of a fish cloudy eye are not always obvious, whereas the symptoms of fish Popeye are very noticeable.

Is Cloudy Eye in Fish Contagious

The cloudy eye can be contagious to new fish. It’s best to avoid exposing your fish to others who may have the condition and make sure you give them all the proper care.

If you notice that your fish has a cloudy eye, you should take steps to determine the cause and treat it accordingly.

Does Cloudy Eye in Fish Go Away

In most cases, the cloudy eye will clear up on its own within a few days. If the condition does not improve after a few days, then it is important to consult a veterinarian.

The cloudiness of the eye in fish is usually caused by a bacterial infection and typically clears up on its own within a few days.

If the infection is severe, however, the fish may require antibiotics or surgery to remove the bacteria.

Aquarium Fish Cloudy Eye

Beautiful aquarium fishes may suffer from this eye cloudy problem. Betta fish cloudy eye, goldfish cloudy eye, discus fish cloudy eye are major concerns for aquarium fishes eye.

The cloudy eye is a common problem with many tropical aquarium fish.

If your aquarium is not well maintained, pollutants build up over time and can create a cloudy environment that inhibits the fish’s ability to see properly.

Regular water changes will help clean the tank and remove any pollutants that may be causing the cloudiness, while also providing healthy aquatic life for your fish.

Fish need water to live and swim in, so if the water is murky or cloudy, the fish may not be able to see as well and could become injured and fall into a secondary infection.

The cloudy water or poor water condition can also contain bacteria that can make the fish sick and cause fish diseases.

Saltwater Fish Cloudy Eye

Saltwater fish are known for their vibrant colors and patterns, but some species can suffer from cloudy eyes.

This is a result of the fish’s oil glands producing excess oils, which cause the eyes to become cloudy.

The cloudy eye is most commonly found in tropical fish, but it can also be seen in some saltwater fish.

It’s not always clear what causes the condition, but it may be caused by environmental factors (such as pollution) or by injury.

The condition can vary in severity, and affected fish may appear normal or slightly motley. In severe cases, the fish may have difficulty seeing and may swim aimlessly around.

Treatment typically involves removing excess oils from the fish’s eyes using a chemical solution or a surgical instrument.

Frequently Asked Questions

How Long Do Cloudy Eyes Last in Fish?

If the cloudy eye is temporary, it will usually clear up within a few days. When it does not go away in a short period of time, the fish may have an infection or other health condition and should be seen by a veterinarian.

Can You Eat Fish With Cloudy Eyes?

Fish with eye problems should not be consumed for safety reasons because it indicates an unhealthy animal that will adversely affect one’s health if consumed.

Can Cloudy Eyes Kill a Fish?

Fish’s eyes are cloudy or filled with mucus, they might not be able to see as well and could become prey for predators or parasites.

In some cases, the fish might also develop infections due to its poor vision.

In severe cases, cloudy eyes can lead to death if not treated well.

How Does the Fish Eye Work?

Understanding fish vision is necessary. The eyes of fish are specially adapted to their aquatic environment.

The cornea and lens of a fish’s eye are curved in order to compensate for the refraction of light that occurs when it passes from water to air.

This curvature also gives fish a wide field of vision, allowing them to see in all directions at once.

Fish have a layer of cells called the tapetum lucidum behind the retina that helps them see in low light conditions.

This layer reflects light back through the retina, which increases the amount of light that is detected and improves vision in darkness.

Fish eyes do not have a lens. Instead, they have a mirror-like surface called the tapetum lucidum.

This surface reflects light back through the retina, which increases the amount of light that reaches the light-sensitive cells. This makes it possible for fish to see in low-light conditions.

What is the Term “Fish Cataract” & Can Fish Get Cataracts?

A fish cataract is a growth that can form on the lens of a fish’s eye. This type of cataract can cause blindness in the fish.

The growth may be caused by a number of factors, including genetics, age, injury, or infection.

Nutritional deficiencies, particularly a lack of Vitamin A, can lead to the development of cataracts in fish.

Treatment for a fish cataract may include surgery to remove the growth, antibiotics to treat any infection, and/or steroids to reduce inflammation.


  1. Sahay, P., Pandya, I., Maharana, P. K., & Titiyal, J. S. (2018). Cloudy Cornea with Arcus Juvenilis in a Case of Dense Deposit Disease. Case Reports, 2018, bcr-2018.
  2. Hargis Jr, W. J. (1991). Disorders of the eye in finfish. Annual Review of Fish Diseases, 1, 95-117.
  3. Krise, W. F., & Smith, R. A. (1993). Communications: Eye abnormalities of lake trout exposed to gas supersaturation. The Progressive Fish‐Culturist, 55(3), 177-179.

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