Why Do Guppies Lose Their Color? (7Reasons+Prevention)

Guppy fish are famous for their attractive and bright colors, especially when it comes to male guppies. But, guppies can lose their color and look pale and ill for various reasons and finding the particular reason behind it is essential. So, Why do guppies lose their color? Let us find out.

Guppy will lose their color if suffering from illness. Inadequate water quality, stress, poor nutrition food, age, and light deficiency in an aquarium are the other possible reasons. Provide guppy nutritional food and adequate water condition with stable water parameters to prevent such issues.

We will discuss the reason behind guppies losing their color and the prevention to take for avoiding guppies from such issues in this article. Also, we will read about if a pregnant guppy loses color or not. So, let us get into it

My guppy is losing its color.

There can be various reasons behind your guppy losing its color. Some of them are:

  1. Stress
  2. Injury
  3. Disease

Guppy usually doesn’t lose their color once they get it, and if they lose color, something goes wrong.

If your guppy is losing its color at night, then there is nothing to worry about as guppies are diurnal and sleep at night.

It is natural losing color and get pale while sleeping in fish. However, your guppy will get its color back when it gets active in the morning.

There are various other reasons behind your guppy losing its color, which we will discuss in this article.

How do guppies get their colors?

Guppies don’t get their color when they are born.

You will find your guppy fry will not have color.

Your guppy fry will look greyish and with no color.

Guppies get their beautiful color weeks after getting born.

However, the time of developing color in guppies will depend on the genotype, tank water condition, and the nutrition provided to your guppy.

Usually, guppy fry gets its color in an average of five to seven weeks after getting born.

Male guppies appear to be more colorful than female guppies, which takes us to our next topic.

Why are male guppies more colorful than female guppies?

Chromosomes are the reason behind male guppies being more colorful than female guppies.

Male guppies have chromosomes passed to the male guppies only and are inherited almost unchanged.

Chromosomes are not passed to female guppies, which is why female guppies do not have colors like male guppies.

Male guppies use their color to attract female guppies.

Female guppies get attracted to male guppies with bright colors rather than male guppies with dull colors.

Also, bright colors indicate your male guppies’ health. So if your male guppy has bright color, then their health is good.

Guppies will not change their color once they develop it anyhow. If they are losing their color, there is some issue.

Why is my guppy turning black?

Guppy fish turn black when toxic chemicals like ammonia are present in water.

Ammonia spike in your guppy’s aquarium will burn the guppy’s gills, making them turn black.

There can be an ammonia spike in your guppy’s aquarium if you are not doing a regular water change or not using a good filtration system.

Providing your guppy with an adequate water conditions with a stable water parameter with a pH level of 6.8-7.8 is essential.

Reasons behind guppy losing its color

There can be several reasons behind your guppy losing its color:

  1. Your guppy is growing old
  2. Your guppy is under stress.
  3. There are some issues with the water condition and parameters.
  4. Your guppy is suffering from some illness.
  5. Your guppy is not getting the nutritional diet they need.
  6. Your guppy is sleeping.
  7. Your guppy is not getting enough natural sunlight.

Growing old

With time when your guppy gets old, it will start losing color.

We can do nothing to get our guppy’s color back.

Getting aged is a natural process, and we can do nothing about this fact.


Stress can be the primary reason behind your guppy losing color.

There can be various reasons behind your guppy coming under stress:

  1. Aggressive and non-compatible tankamtes.
  2. Any injuries.
  3. Inadequate water condition.
  4. Unstable water parameters.
  5. Overcrowded tank condition.

Guppies are hardy fish and can live in a wide range of water conditions.

Guppies don’t come under stress very quickly. But guppies are soft when it comes to unstable water parameters and poor water conditions.

An overcrowded tank and the presence of aggressive tankmates will also make your guppy come under stress.

Guppies need a lot of free space to live happily and healthily.

It is possible that your guppy has an injury or is suffering from health issues that are causing them stress.

Guppy in stress will start losing its color.

Also read: Are My Guppies Stressed?

Inadequate water condition and parameters

Your guppy will start losing its color in such conditions:

  1. If there is inadequate water condition provided to guppies.
  2. If the water temperature of your guppies aquarium is not stable.

Your guppies will not live comfortably in poor water conditions and water parameters that are not stable.

Guppies prefer to live in adequate water conditions with stable water parameters.

By poor water condition, we mean the water which contains chlorine, heavy metals, ammonia, and nitrite like chemicals.

These chemicals are very harmful to your guppies and affect your guppy’s health.

Guppies will thrive in water with ammonia and nitrite at 0ppm and are free of chlorine.

Providing a stable water temperature is essential as the unstable water temperature will cause stress in your guppy.


Suffering from several illnesses can also cause your guppy to lose its color.

Some diseases which can affect your guppy’s bright color are:

  1. Fin rot
  2. Guppy ich
  3. Fungal skin infection

It is not necessary that diseases will directly affect your fish color.

Diseases cause stress to your guppies, and guppies under stress will start losing their color.

Common diseases that can affect your guppies include dropsy, swim bladder disease, and ich.

Also read: How to Cure Guppy Ich?

Poor nutrition food

FoodServing QuantityNo of Times
Veggie pelletsOne pinch at a time 2-3 times a day
Brine shrimpOne pinch at a time 1-2 times a week
BloodwormOne pinch at a time 1-2 times a week
Tubifex wormOne pinch at a time1 time a week
Mosquito larvae10-15 pieces2-3 times a week

Guppies are omnivore fish and require both meat and plant matter in their regular diet to thrive.

Usually, guppies will feed on anything you will provide to them.

Providing your guppies pellets and flake food is okay, but you should include various food to develop attractive colors in your guppies.


Guppies are diurnal and prefer to sleep at night.

Guppies are active in the daytime and rest at night. While sleeping, your guppy will get pale and will have less color.

It is entirely normal in such a situation, and there is nothing to worry about the color.

Your guppies will regain their colors right after waking up when the lights turn on in the daytime.

Also read: Is My Guppy Sleeping or Dying?

Lack of natural light

Lack of light in your aquarium can cause your guppy to lose its color.

If you place your aquarium in a place where there is no source of direct or indirect sunlight, then your guppy may start losing its natural color.

Prevention to take for guppy losing color

These are some prevention you should take to avoid your guppy fish losing color:

  1. Provide your guppy with a stable water parameter.
  2. Make sure to provide your guppy with adequate water conditions.
  3. Regularly check your water condition. If there is any spike in ammonia, nitrite, chlorine, or heavy metal, eliminate them by properly cycling your water.
  4. Use a water conditioner to eliminate chlorine, nitrite, and heavy metals like chemicals. 
  5. Provide your guppies with a nutritional diet in a regular manner.
  6. Ensure that there is nothing in their surroundings that can cause stress to your guppies, like angry tankmates and overcrowded tanks. 
  7. Provide your guppies enough space to live comfortably and happily.
  8. Keep a constant check on guppies, whether they are suffering from disease or any physical injury like rotten fin or spots all over the body. 
  9. Immediately isolate your guppies in a separate tank if you find your guppy suffering from any disease and give them medical treatment. 

What to do if my guppy is losing color?

Look for any injury or physical signs like spots in your guppy’s body or rotten fin when you detect that your guppy is losing its color.

If your guppy is suffering from any disease or infection, then isolate your sick guppy in a hospital tank and treat them.

Your guppy will get its color back once they get healthy again.

If disease or any infection is not the reason behind your guppy losing its color, there are other issues.

Check your water parameter to see if it’s stable or not, as unstable water parameters will cause stress to guppies and, as a result, they can start losing color.

We recommend adding a heater to your guppy fish tank to ensure stable water temperature.

We recommend using the Fluval M200 Submersible heater for your tank.

You can buy this product at amazon: Fluval M200 Submersible Heater.

Look if the water is clean or not, as poor water conditions can also cause stress to your guppy.

Performing a weekly water change of at least 35% will help you keep the water clean.

Make sure to treat the water using a water conditioner to dechlorinate it.

We recommend using the API water conditioner to treat the water, as it will help you eliminate chlorine, chloramine, ammonia, nitrite, and heavy metals from the water.

You can buy this product on amazon: API TAP WATER CONDITIONER.

Also, use a good filtration system with biofilter media to keep the water clean from excessive waste and protect your guppy tank from harmful toxins like ammonia and nitrite.

You can consider using a Fluval high-performance aquarium filter for your tank, as it will ensure that your water is clean and protected from harmful toxins like ammonia and nitrite.

You can buy this product at amazon: Fluval High-Performance Aquarium Filter.

Keep a regular check on ammonia, nitrite, and nitrate, and make sure to maintain ammonia and nitrite at 0 ppm, whereas nitrate should be below 20 ppm.

We recommend using the API freshwater master test kit to check the ammonia, nitrite, nitrate, and pH level of your fish tank, as it shows an accurate result.

You can buy it from amazon: API FRESHWATER MASTER TEST KIT. 

Your guppy will lose its color at night when sleeping. So, it is completely normal if your guppy is pale and has less color at night.

Also read: How Can I Enhance My Guppy Color?

Do female guppies lose their color during pregnancy?

Female guppies can have a faded color when they are pregnant.

This is because your pregnant guppy will develop a gravid spot behind the anal fin, which will get darker over time.

Also, your guppy’s body shape will get change. Your pregnant guppy will have a big round belly.

Pregnant guppy can quickly come under stress also, as they get weak and the chances of getting bullied increase.

There are other symptoms to detect if your female guppy is pregnant:

  1. Gravid spot
  2. Big round belly
  3. Loss of appetite
  4. Hiding behavior
  5. Aggressive nature
  6. Swimming in one place

A pregnant guppy’s gestation period lasts an average of 25-30 days.

Your pregnant guppy will get its color back once they release the fry.

Also read: Is My Guppy Pregnant?


Guppies can lose their color when under stress, suffering from a disease, and living in poor water conditions.

Make sure to keep your guppy’s environment stress-free by not keeping any aggressive tankmates and providing them an adequate water conditions with stable water parameters.

Look for injury and symptoms of illness like rotten fin or spots over the body if your guppy is losing color.

Take immediate action by placing them in a separate tank and performing recommended medication.

If an illness is a reason behind losing color, then your guppy will get its color back once it is recovered.

Reference: ResearchGate, Journals, NCBI, DOE PAGES

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