why do fish turn white when they die?

Why Do Fish Lose Their Color When They Die? (Fish Turning White)

If you notice your fish turning white and dying, there could be many reasons responsible. It’s not unusual for fish to change color as they die. However, it can sometimes be a sign of a health condition or environmental issue.

Most fish lose color as they die because their bodies lack oxygen and nutrients. The body also stops circulating air and can’t absorb sunlight. Some fish fade to a duller color, while others turn completely white. If you notice your fish becoming translucent before or after they die, there’s likely not enough oxygen in the tank. Similarly, environmental factors, such as poor water quality or overcleaning, are also to blame.

Keep a close eye on your fish’s coloration, especially if it happens before they die. Any changes to their appearance can indicate that something within the tank isn’t quite right. As a result, you’ll need to act fast to save your surviving fish and provide a healthy environment.

Why Do Fish Turn White When They Die?

Fish sometimes turn white as they die. While this might be surprising to owners, it’s more normal than you might think. As we’ve already explained, when a fish dies, it no longer has air, light, or nutrients circling around its body, causing it to become white. Also, as soon as the fish dies, it starts to rot, which is why it turns white so quickly.

However, a dead fish turning white sometimes indicates that your water parameters or tank positioning aren’t quite right, putting your surviving fish at risk. That’s why it would help you to understand why your dead fish changed color in the first place. 

Several things determine a fish’s coloration, and if any of them aren’t suitable, they can turn your fish white. These factors include:

Water Quality Fluctuations

Poor water quality is one of the primary reasons for fish turning white and dying. Fish have specific water requirements – the pH and water temperature must be in perfect condition for fish to survive. It varies depending on the species, but this is something that all fish have in common.

Most tropical fish do well with a pH of between 6.8 to 7.8. Goldfish and other cold-water species require the water’s pH to be between 7.0 to 8.4. Similarly, rapid water changes can be harmful – and even fatal.

Several things can cause the pH levels to become unbalanced, including:

  • Trace mineral content
  • The type of substrate in the tank
  • The chemical concentration of the water
  • Failure of the filtration system
  • Too many driftwood decorations
  • Certain medications

If any of these things cause the pH levels to drop or the water conditions to become unsanitary, your fish will turn white and die of the exposure.

Luckily, there are things you can do to restore your aquarium’s pH. This includes:

  • Carrying out a water change to restore the tank’s natural pH balance
  • Changing your substrate
  • Increasing the aeration
  • Adding a small amount of baking soda to the water

Then, keep an eye on the rest of your fish to ensure that your surviving fish don’t turn white or become discolored.

why do fish change color when they die?

Tank Overcleaning

Cleaning your fish tank is essential because it:

  • Removes waste, such as ammonia, nitrites, and nitrates
  • Prevents unwelcome growths
  • Keeps the filter functioning properly

Fish need their tanks cleaned once or twice a month. Depending on how often you clean yours, you should aim to replace 10-20% of the water in one go. Avoid changing more than 40% in one sitting, though, as this can cause problems for the tank and the fish living in it.

However, cleaning the tank too frequently causes your fish to become stressed out. Not only will this cause them to turn them white or become dull in coloration, but it can lead to an early death.

That’s because if you replace too much water at once or too often, the beneficial bacteria that had previously built up within the tank will die.

It’ll also mean that your fish have to undergo the cycling process to re-add the bacteria back in. Without them, ammonia and nitrites will overpopulate the tank, causing your fish to get sick.

Nutritional Deficiencies

Your fish’s diet plays a large part in coloration maintenance. While all fish have different nutritional requirements, they all need a high-quality, specialized diet containing the correct amount of nutrients, vitamins, and minerals to stay healthy.

Most fish flakes and pellets are specially formulated to provide each fish species with the things they need. However, some also need a selection of:

That’s why you must research the nutrients your fish require and choose compatible species for your community tank to ensure they’re not getting access to the wrong types of foods. When different fish are in one tank, there’s no way to separate their food without a lot of effort.

Nutritional deficiencies are responsible for turning your fish white and will cause them to die. The Pet Food Manufacturers Association explains that, as a rule of thumb, most fish require:

  • Protein, which supplies the ten amino acids they need
  • Fat, for energy and a source of essential unsaturated fatty acids
  • Vitamins, including A, C, D, E, and K
  • Minerals, including calcium, phosphorus, iron, iodine, and magnesium

Some fish foods contain pigment enhancers, which bring out the natural colors of the fish. These enhancers include shrimp meal, Spirulina algae, and lutein.

As soon as a fish stops eating and dies, its colors will fade. Some fish become dull, while others turn white. It all depends on how long the individual fish stopped eating before its death.

Poor Oxygen Levels

Once a fish dies, the blood and organs stop receiving O2, and the body quickly loses its once-vibrant coloring. This is an entirely natural process and shouldn’t cause any concern.

However, a fish turning translucent white before it dies indicates there’s not enough oxygen in the tank. This also suggests the fish died of suffocation. Signs of not enough oxygen include:

  • Gasping at the surface
  • Moving less
  • Appetite loss
  • Labored breathing

Thankfully, there’s plenty you can do to increase the aquarium’s oxygen levels. For starters:

  • Carry out a large water change, replacing 60% of water
  • Add more plants
  • Provide substrate that allows plants to grow
  • Increase your tank’s surface area
  • Increase surface agitation
  • Decrease the number of fish you have

A lack of oxygen won’t just cause your fish to turn white when they die. It’ll leave them susceptible to several health conditions, too.

Lack of Sunlight

It might surprise you to know that fish need an element of sunlight to stay productive and healthy. Some fish species, such as koi and goldfish, need the sun to develop healthy skin pigmentation.

If fish don’t get enough natural sunlight, their scales appear lighter and fade over time. Similarly, fish kept in dark areas of the home are at risk of turning white altogether. This isn’t something that only happens when fish die – their scales can fade at any time without the right lighting conditions.

To prevent this problem from happening, put your tank somewhere that it can receive up to 12 hours of natural sunlight a day. However, don’t place it in direct sunlight, as it’ll increase the water temperature and wreak havoc on the ecosystem. Filtered light is always best.

Artificial Light

Bright artificial lights are also responsible for fading your fish’s scales. As described by Science Direct, light that’s too intense can also be stressful, which is another primary cause of whiteness in fish. Aquarium lights are used to:

  • Keep fish healthy
  • Help plants grow
  • Allow owners to see their fish properly
  • Illuminate the fish’s colors

However, you shouldn’t have the lights too bright – they should replicate natural lighting conditions if you don’t have access to natural sunlight. Similarly, fish sleep at night, so turn them off when you go to bed to allow this and preserve your fish’s scale coloration.


When fish get stressed, it shows on their scales. It’s easy to tell when something’s wrong because their scales become dull and colorless. Overly stressed fish eventually die. When they do, you’ll notice they appear white rather than bright and vibrant. This indicates your fish were mentally unwell when they died.

One of the most common causes of stress in fish is aggressive behavior from other tankmates. If they’re continually chased and harassed by other fish, their scales will become dull. And the more stressed your fish are, the quicker they’ll lose their colors. The other main signs of stress include:

  • Frequent hiding
  • Glass surfacing
  • Jumping out of the tank
  • Fin rot
  • Loss of appetite
  • Constant sickness

When it comes to your fish’s appearance, you might notice:

  • Dimmer colors that appear dull and lifeless
  • Fins that seem ashy or thin
  • Scales that appear flaky or frail
  • Stripes that fade away or appear faded in color


Sick fish lose their color. How much so depends on the species and the type of illness they’re suffering from. If one of your fish suffers from an illness that’s gone to the advanced stages, it’ll experience significant changes to its appearance, and the color will drain from its scales at a rapid rate.

It’s not easy to tell when your fish is sick, so observe for any of these signs:

  • A lack of appetite
  • Holes, bulges, or spots
  • Protruding or lost scales
  • The fish getting attacked by other fish in the tank
  • Torn fins
  • Unusual swimming patterns

These are common indicators that your fish is close to death. If it’s already died and appears white, monitor the healthy fish in case of a contagious condition.


Fish are commonly prone to bacterial, fungal, viral, parasitic, and protozoal infections. Unfortunately, these things are easily transmitted to other fish, putting the entire tank at risk. Poor water quality and rising chemicals are likely to worsen the problem. The most common infections include:

Some infections cause fish to lose their scales. This is an extreme reaction, but it indicates that the fish are in the advanced throes of illness. It also explains why your fish turned white when it died.

Age and Genetics

It’s common for fish to lose their color as they get older. Genetics have a significant part in this, as they determine whether fish stay bright and colorful or fade over time. Some cells don’t live as long as others, so it’s natural for fish to fade to white before they die.

Why Do Fish Change Color When They Die?

Not all fish turn white when they die. Some go from being bright to dull, while others change color altogether. Environmental factors are usually to blame.

Like fish turning white, poor water conditions and unsuitable parameters can unexpectedly transform your fish’s scales. Stress is also a likely explanation. Several things can cause stress, such as:

  • Problems with other fish
  • Unsuitable water temperature
  • Dirty water
  • Lack of hiding places
  • Poor diet

As a rule of thumb, stressed fish are unhealthy fish and are a leading cause of death. Even though it’s not always easy to tell when something’s wrong within the tank, paying attention to your fish’s demeanor and regularly testing the water will help preserve your fish’s coloration.

What Does a Fish Look Like When It’s Dead?

It’s relatively obvious to determine when a fish has died. Not only does it stop moving, but it’ll look different from the rest of the fish. It’s not pleasant to see a dead fish floating in the tank, but knowing what one looks like can help you diagnose death when the time comes.

You can check that the fish is genuinely dead by paying attention to the following:

Sunken Eyes

When fish die, their eyes become sunken. This is one of the most evident signs that they’re dead. Similarly, when you remove the fish from the water, they’ll stare motionless without moving. If the pupils rotate downward, the fish is still alive, and you need to put it back into the water.

fish lose color and die

Cloudy Pupils

Some fish species, such as pufferfish, walleye, and scorpionfish, develop cloudy eyes after death. Similarly, if your fish had been in poor health before death, it will die with milky eyes. Such health issues include:

  • Dietary deficiencies, specifically a lack of vitamin A
  • Poor water quality
  • Ammonia poisoning
  • Cancer

If your fish develops cloudy eyes and a white-scale appearance, your fish likely died of a health problem or unsuitable water conditions.

Stiff Body

A dead fish should be stiff as a result of Rigor Mortis setting in. If your fish feels soft and floppy when you scoop it out of the water, it’s likely still alive, or it might have only just died.

Fish that have died after jumping out of the tank will have cracked, dried bodies due to dehydration. Some of the scales might fall off as a result.

Lack of Pigmentation

As we’ve already mentioned, dead fish lose their pigmentation due to the lack of nutrients, oxygen, air, and light. This is why you’ll notice your fish looking white or dull. Unhealthy or stressed fish are unlikely to possess their full coloration, so it’s normal to see dead ones looking dull and colorless.

Floating on the Surface

Smaller dead fish, such as guppies and tetras, float. Larger ones, like cichlids, are more likely to sink to the bottom. That’s where you’ll find them when you go to inspect your tank. However, if your fish has been dead for a while, gasses will build up, causing it to rise to the surface. This will also give them a bloated, rounded appearance.

While it’s normal for fish to lose color and die, it’s not normal if the fish that are still alive start turning white or becoming dull too. There are so many factors that can contribute to this, but with a few detective skills, you should have success in determining the issue.