Cloudy Eye Fish Disease: The Signs, Causes, and Treatment

Charlie Morton

Charlie Morton


Cloudy Eye Fish

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It’s always distressing to notice your fish suffering from health issues, and cloudy eyes are not an uncommon complaint.

According to fish health specialists,, cloudy eyes are most often the result of an injury, but several other causes and factors can influence or exacerbate the issue, too.

Here we’ll look at the main causes, and what you can do to treat them.

Key Takeaways

  • Cloudy eyes can be a symptom of a wide variety of causes. Infections, genetics, poor water quality, chemicals, and injury can all lead to the problem.
  • The symptoms may be treatable depending on the cause. In some cases, cloudy eye disorder can even clear up by itself.
  • If your fish becomes permanently blind, its quality of life will be severely compromised, leading to problems with feeding and becoming more vulnerable to other fish, sharp objects, etc.

What Is Cloudy Eye in Fish?

A cloudy eye is something that can occur in a fish, usually due to damage to the eye (since fish typically do not have eyelids to protect their eyes from damage). Still, it can also result from a fish’s immune system being low.

This typically looks like a cloudy layer, sometimes making the eye appear white or gray.

When a fish’s eye is damaged, this cloudiness may be present in the outer eye (on the cornea) or the inner eye (the rest of the eye structure).

You must note that outer eye damage is usually less serious than damage on the inner part of the eye, making it easier to treat and cure the cloudiness.

What Causes Cloudy Eyes in Fish?

Determining the cause of cloudy eyes in your fish can help you learn the next steps needed to treat or cure it.

Be sure to use this article as a general guide, though, and if you believe your fish may be sick for one or more of these reasons, consider consulting an aquatic veterinarian.


Fish can occasionally be born with cloudy eyes and this trait can be passed through genes down family lines.

To be sure of this, you’ll need to be certain that your fish’s eyes have always looked like this since he hatched. In these cases, cloudiness will usually be present in both eyes to a similar extent.

Some species, such as pufferfish and rabbitfish, have a naturally white sheen on their eyes, which can easily be mistaken for cloudy eyes.

If your fish develops cloudy eyes, you’ll want to first research your fish’s species, as it may be the case that cloudy eyes are common in your pet’s gene pool.

Ammonia and Nitrate Levels

When it comes to your tank parameters, you’ll want to keep the levels of ammonia at zero and nitrate levels below 20 ppm.

You can ensure this by installing an efficient filter, regularly changing the water, and removing any waste build-up, such as fish waste or uneaten food, that may settle on the bottom of the tank.

This is commonly overlooked in new tanks, as many people often forget to monitor the nitrogen cycle in their new aquarium.

In short, if you regularly maintain and test the nitrate and ammonia levels in the tank to make sure they’re suitable for your species, then your fish should not acquire illnesses related to these levels or develop cloudy eyes as a response.

Chlorine & Chloramine Poisoning

If you are using tap water to fill your tank, ensure that chlorine and chloramine have been removed.

You can remove chlorine by pumping air through the water to make it dissipate faster or letting the water sit for approximately 24 hours.

Chloramine can only be removed via water conditioning or heavy carbon filtering, which can be purchased at your local pet shop.

If the water is left untreated, these could irritate your fish’s eyes and cause them to become cloudy, as well as make your fish very sick.


You should be careful to only add any medication to your tank at the correct doses.

If you add too much medication, this can cause eye problems for your fish, such as cloudiness, due to either an adverse reaction to the medication or due to the effect of the medication on the conditions of the water.

Poor Diet

A deficiency in vitamin A, which is crucial for healthy eyes, can also cause cloudy eyes.

If you believe this could be the case, making adjustments to their diet could be beneficial. Ensure they have the perfect balance of vitamins and minerals to stay healthy and happy.

If they’re deficient in other vitamins, this will compromise their immune system, making them more susceptible to illnesses and infections, so be sure to give them a well-balanced diet so they can remain in good health.

Physical Injury

When determining what may be causing your fish’s cloudy eyes, it’s important to note both. If both eyes are cloudy, then it’s likely caused by illness or infection.

However, if just one eye is affected, then it’s quite likely to be a physical injury or trauma to the eye. Sometimes it’s caused by fights between fish and it can result in discomfort.

If you determine the cloudiness has been caused by physical injury, try to figure out what and when this could have been. Possibly a sharp angle or point on some of your aquarium’s decor?

If not an object, it could have been caused by a fight with a tank mate. If housed with any aggressive species that may have attacked your fish, you may want to consider moving them to a different tank to prevent any future damage to either fish or even death.

This type of injury will usually clear up by itself, but keep a close eye on it. If your fish contracts a bacterial eye infection, this could cause the cloudiness/milkiness to worsen, so if this occurs, be sure to see a vet.


According to fish health specialists at, cataracts can be caused by many factors such as poor nutrition, genetic issues, and parasites such as eye flukes.

Causing one or both eyes to become opaque, cataracts can eventually cause total blindness. Sadly there remains no known treatment at present.


Parasites, such as eye flukes, are often present in fish tanks but usually wait for poor water conditions or a weakened fish to strike.

If you encounter an outbreak, and you’re certain that’s what it is, firstly, medicate your tank with appropriate medication.

Parasites can cause damage to your fish’s body, causing tears in fins, lesions, and other symptoms such as cloudy eyes.


Cloudy Eye Fish

To follow on from the parasitic infections, let’s look at infections more broadly. Whilst some can be caused by parasites, bacterial or viral infections can cause others.

A lowered immune system can result in your fish getting an infection, which can cause cloudy eyes as a primary symptom as your fish tries to fight it off.

Parasites and bacteria can be brought into the tank when introducing new fish. This is why it’s often recommended to quarantine new fish you bring home before adding them to a community tank.


Does Cloudy Eye Fish Disease Go Away by Itself?

Whether or not your fish’s cloudy eyes will clear up by themselves entirely depends on the cause and the favorable conditions you create for their healing.

Can Cloudy Eyes Kill a Fish?

In the wild, cloudy eyes are likely to cause a fish to die as the fish is unable to see. Cloudy eyes can make them extremely vulnerable to predators. In captivity, your fish has a much greater chance of recovery.

As a cloudy eye is a symptom of illness or something wrong and not an actual illness in and of itself, it’s best to usually take it as a sign that something more serious is affecting your fish.

It is the illness or infection causing the cloudy eyes that could be deadly to your fish, so whilst cloudy eyes won’t cause your fish to die, the root cause of the problem could lead to your pet’s demise unless you seek appropriate treatment.

Is Cloudy Eye in Fish Contagious?

Cloudy eye disease is a term describing the symptoms of various diseases, rather than being a contagious disease itself.

The infections that cause cloudy eyes such as eye flukes and bacteria, however, can be contagious.

Can Cloudy Eyes Be Treated?

Cloudy eyes may be treatable depending on the cause of the symptoms. If the cloudy eyes are caused by a parasitic infection, then medicating the tank to remove the parasite will usually help the eye problem to clear up.

In other cases when a cloudy eye is caused by a cataract or severe injury, it may remain permanently cloudy.

Can a Fish Live With One Cloudy Eye?

If your fish has one permanently cloudy eye, it should be able to continue living a happy life as long as the other eye remains clear.

Can a Fish Continue to Live With Permanent Blindness?

If both eyes become cloudy, your fish may become completely blind, compromising its quality of life and leaving you to decide on the best line of action.

Blind fish can inflict further injuries on themselves by bumping into sharp objects, and may also become more vulnerable to their tank mates.

We discuss how to feed a blind fish in our dedicated article here.

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