The cloudy eye is a very common disease among aquarium fish that can lead them even to death. Let’s talk about what is cloudy eye, what are the causes it, and how to cure cloudy eye disease.

What is the Cloudy Eye of Aquarium Fish?

Cloudy Eye is a disease that affects many fish varieties in the aquarium hobby. The infected fish’s eyes get hazy to the point of becoming white, and without treatment, they would lose their entire vision. But in many cases, it is can be a sign of another disease rather than a sickness in itself. 

Cloudy eye of betta fish
Cloudy eye of Betta fish

Do Cloudy eyes go away with the Treatments?

Yes, Cloudy eyes can be treated and cured. But you have to identify the disease at an early stage and carry out proper treatments. Otherwise, it can cause loss of vision and even the death of your loving pet fish. 

Cloudy Eye Disease Symptoms

The basic physical symptom of the cloudy eye is as its name suggests. A murky white or gray haze can be appeared on one or both eyes of the fish. 

In addition, the fish may display symptoms of discomfort, such as strange behavior and color changes. In the worst-case situation, eyesight loss.

Cloudy eye of African mano
Cloudy eye of African mano

Why has my fish got a cloudy eye?

There can be several possible causes of Cloudy Eyes in aquarium fish. Some of the causes are natural and cloudiness can vanish over time while some cases become severe. Before treatments, it’s better to identify the cause of the disease.

Poor water quality

Poor water quality is the main cause of cloudy eyes as for many other aquarium diseases. It weakens the immune system of your fish.

To maintain good water quality in the aquarium, you should have a good idea about the main water parameters PH, Ammonia, Nitrites, and Nitrates levels. Understanding of Aquarium Nitrogen Cycle and performing regular water changes can reduce the likelihood of poor water quality.

Cloudy eye of Arowana fish
Cloudy eye of Arowana fish

Physical Injuries (Trauma)

Aquarium fish don`t have eyelids to protect their eyes from external emergencies. Therefore a minor abrasion can cause a localized immune reaction in those who don’t have eyelids to shield their corneas. 

As the fish’s immune system swims to the rescue, the cornea on the exterior of the eye might become hazy. The majority of clouded eyes in fish are caused by these physical injuries. 

Most of the time, physical injuries may occur due to sharp edges of tank decorations and other fish attacks. So try to find the root cause and eliminate it.

Cataracts &  Eye Cancers

Cataracts and eye cancers are also caused to the cloudy eyes of aquarium fish. Unfortunately, these cases are somewhat hard to cure. But you can eliminate the risk. There are a lot of factors that can be caused cataracts.

High UV exposure and high concentration of heavy metals in the water raise the risk of different malignancies. Also, it can be occurred due to natural factors like genetics and the aging of the fish.

To prevent cataracts and eye cancers always try to use a recommended aquarium light in your fish tank. There are some aquarium lights that emit high UV. If your fish are in an outdoor pond, make some shades that can cover the pond from direct sunlight. Also, test the water hardness and take necessary actions to maintain the right levels.

How do you treat cloudy eyes?

So as the first step you should check your water parameters PH, Ammonia, and Nitrites. If the levels are worse, immediately perform a 75% water change, and once the water quality is good the fish will normally start to recover their own within 1-2 weeks. 

Also, you can apply aquarium salt with the recommended amount to keep other fungal and bacterial infections away. As well as there are numerous effective treatments available at your local pet store to address this issue yourself. Follow the guidelines as directed. 

But if the damage is severe, immediately contact your fish veterinarian. It’s necessary to start some antibiotics.


I am Prasanjaya who is an aquarium hobbyist for nearly a decade. I wish to help fishkeepers to get accurate and helpful information regarding every aspect of fishkeeping.

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