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Why Are My Fish Turning White?

An aquarist’s worst nightmare is seeing their fish turn white. It could mean the fish is ill or experiencing discomfort. In the worst-case scenario, the situation could become life-threatening.

The best course of action is to analyze the causes listed below carefully.

Reasons Why Your Fish Are Turning White?

fish-turning-whiteSome of the reasons for your fish turning white include the following:

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A. Lack Of Oxygen

Like every other living thing, fish need oxygen to survive, the lack of which can lead to their demise.

Fortunately, your fish can return to its original color if you quickly replete the oxygen supply.

Typical signs associated with lack of oxygen include:

● Gasping at the surface of the water
● Fast breathing
● Lack of appetite
● Unstable balance when swimming
● Rapid gill movement 
● Staying at the filter output, where there’s typically more oxygen
● Lack of activity

Note that it is normal for some species of fish with labyrinth organs (anabantoids) to gasp at the water’s surface.

But if you notice them doing it more often than usual, it could indicate a lack of oxygen.


How To Fix?

Once you notice the signs of your fish struggling to get oxygen, you should act immediately to prevent them from eventually dying.

1. Increase Water Movement

The first thing to do is to ensure you always have the water in your tank moving to ensure high dissolved oxygen levels. Stagnant water can cause oxygen levels to drop rapidly.

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Install quality filters or bubble diffusers that can move water. You can also use a spray bar, wavemaker, or air pump to increase air circulation in your tank.

2. Add Water From a Height

Pouring water into your tank from a height will create bubbles in the tank. It seems so easy that most people doubt its power.

Pour the water at the tank’s center and ensure it isn’t blasting directly at your fish. Make sure that the water is dechlorinated.

3. Add Plant Life to Your Tank

plant-in-aquariumHaving plant life in your fish tank can increase the oxygen level. However, this doesn’t mean you should cram your tank with plants because they only produce oxygen during the daytime during photosynthesis.

In fact, at night, plants use the available oxygen in the tank during a process known as respiration.

So to ensure you’re not creating more problems, introduce just a few aquatic plants at a time. Some ideal ones include Tiger Lotus, Hornwort, Elodea Densa, and Eelgrass.

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B. Lack Of Sunlight

Sunlight is important for some fish. For instance, goldfish or koi will lose their color and turn white due to insufficient sun exposure.

dark-aquariumAn aquarium tank needs about 8-12 hours of sunlight daily. Note that direct sunlight can harm your tank and cause further complications. Also, leaving your aquarium in more sunlight than required can be equally harmful.

How To Fix?

1. Switch To Artificial Lighting

Blue-puffy-fishIf your tank is in a position where your fish cannot receive indirect sunlight for long hours, you can opt for indirect lighting.

You can use LED lights, incandescent or fluorescent lights for your aquarium. Whichever lighting you choose should suit the fish in your tank to be effective.

Note that if you’re using artificial lighting, you don’t need to keep it on all the time. Ideally, you should alternate between leaving the lights on for about 12 hours and then turning them off for the next twelve.

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2. Set Timers

Setting timers is quick and hassle-free to ensure a certain number of light hours for your fish.

C. Poor Diet

Another reason why your fish is turning white can be their diet.

Overabundance or lack of certain nutrients in their feed can be equally troublesome.

Shoal-of-fishHow To Fix?

Different species of fish require different nutrients, and if you have multiple species in your tank, it might be hard to separate their food.

Generally, most fish require food rich in minerals, protein, and fat such as insects or worms.

Some fish, like tilapia or goldfish, feed on aquatic plants, while others might need specialized feed to enhance their pigments.

Due to the versatility of fish nutrition, you must conduct thorough research before feeding your fish.

D. Poor Water Quality

Another reason your fish is turning white is the poor water quality in the fish tank.

Fish need an environment free from harmful elements such as chlorine, ammonia, and nitrates in the tank.

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Signs of poor water quality include:

● White, cloudy water
● High levels of ammonia
● Fish gasping after water change
● Fast algae growth
● Low pH

How To Fix?

1. Don’t Overfeed Your Tank

The fish in your tank may require different quantities of food, but one thing you should never do is overfeed them.

The uneaten food will decompose in the tank, increasing the ammonia levels.

High ammonia levels in the tank decrease its quality and cause further complications.


2. Use Quality Filters

Filters are critical in an aquarium because they keep unwanted elements out of the tank.

Note that the type of tank you use will determine what filter you should use. For instance, saltwater tanks require larger filters than freshwater tanks.

Also, since there are three different filtration systems (mechanical, chemical, and biological), you must choose one that best suits the fish in your tank.  

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E. Stress

Stress is one of the most common causes of fish turning white. There are many reasons why your fish might be feeling stressed.


● Overcrowding
● Frequent water changes
● Frequent shifting from one tank to another
●Presence of other incompatible/ aggressive fish or aquatic organisms 

Apart from turning white, stress can lead to the fish gasping for air, crashing at the bottom of the tank, and showing a lack of appetite and energy.

stressed-fishHow To Fix?

1. Make Sure Fish are Compatible

If your tank has more than one fish species, make sure they coexist. If there’s a ‘bully’ fish, keep it separate from the rest.

Also, when introducing a new fish into the tank, ensure you do so under the right conditions.

2. Properly Feed Your Fish

Feed the fish in your tank simultaneously and give them a balanced diet. If there is any leftover feed, gently take it out.

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3. Be Consistent

Sudden changes in fish’s environment can cause stress, so be consistent in maintaining water parameters such as pH, temperature, and ammonia levels.

If you still can’t find the cause of their stress, you will need to consult a professional.

F. Disease/Illness


Disease or illness might be a reason why your fish is losing color. It is a tricky situation because diagnosing an illness is quite hard.

In most cases, you might need to refer to a vet. You also have to keep in mind whether the illness is contagious or not.

The general signs that hint toward an illness or disease include:

● Loss of appetite
● Tail or fin rot
● Less activity
● Unstable swimming
● Change in physical appearance

There are different illnesses or diseases that can plague a fish, depending on its species. Be careful when handling a sick fish and take safety measures as advised by the vet.

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Other causes of your fish turning white might be genetics or old age.



Nothing can be more frustrating for an aquarist than to see their fish turn white. The reasons can be pretty broad, ranging from poor water quality to poor diet.

However, with proper diagnosis and corrective measures, you can get their color back, as explained in this thorough guide above. 

If all else fails, we advise consulting an experienced vet without delay.

Why Are My Fish Turning White?

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