Can Goldfish Lose Their Black Markings? And Why It’s A Good Sign?

Can Goldfish Lose Their Black Markings

Goldfish can lose their black markings. This can happen due to genetics, stress, certain foods, illness, poor water quality, or parasites.

There are several reasons why a goldfish may lose its black markings and even change color. Sometimes, these changes can mean your goldfish is ill, but in most cases, there are other reasons why this is happening. If you have questions regarding the appearance and coloring of your goldfish, check out our findings below.

Will Black Markings On A Goldfish Disappear?

Many goldfish lose their black markings at some point.

In most cases, it isn’t anything to worry about because there are many reasons why the appearance of a goldfish may change in this way.

However, you should know that if you notice your goldfish is losing its markings, it could be a sign of illness.

But before you go running out to the pet store in hopes of finding a treatment to cure your fish, take a minute to find out why the black markings are disappearing.

Some reasons why a goldfish loses its black markings include the following:

  1. Genetics,
  2. Stress,
  3. Color Enhancing Foods,
  4. Illness and Parasites,
  5. Poor Water Quality.

So, yes, black markings on a goldfish can definitely disappear. In some cases, this can even be a good thing.

Some fish experts say black markings on a mostly golden goldfish are caused by “melanophore migration,” which can be the result of damaged skin cells.

So, if those damaged cells are gone, that could signify a positive change for your fish.

Now let’s talk about all the reasons why your goldfish can loose their black markings.

Let’s start with how genetics might be behind the disappearance of those black markings on a goldfish.

Reason #1: Goldfish Genetics

Goldfish changes can be due, in large part, to their genetics.

Many goldfish change color and lose their black markings as they grow and age.

It doesn’t usually have anything to do with feeding, water, or overall care.

But to rule those things out, you’ll have to check them first.

How much of the black markings a fish may lose generally is determined by its genetic make-up.

Young goldfish usually end up looking like at least one of their parents.

However, identifying the parent of a goldfish can be difficult unless you are a professional goldfish breeder or are paying really close attention to what’s happening in your tank.

This means you might have trouble determining the genetics of a goldfish if you purchased it from your local pet shop.

So, it might be hard to know if genetics is the real reason that your goldfish will lose their markings.

If you don’t know the genetics of your goldfish, perhaps your goldfish is losing its markings because it is stressed out.

Reason #2: Stressed Out Goldfish

Sometimes a goldfish can feel extreme tension, which over time, can lead to them losing their black markings and changing color.

A few things that might stress a goldfish out include the following:

  1. New fish being added to their tank.
  2. Being put in a new tank.
  3. Getting new items added to their tank.
  4. The lighting being changed in their tank.

Yes, a goldfish can get stressed out. And stress can change their demeanor.

It can also make them lose their black markings and make them change color.

The diet of your goldfish can also play an important part in why your goldfish has lost its color.

Let’s take a quick look at how color enhancing foods affect goldfish.

Reason #3: Color Enhancing Foods

There are some fish foods that can make your goldfish change colors by enhancing the subdued colors of the goldfish.

For instance, you might notice your goldfish was a dull orange color, but after feeding them certain foods, their color turns a deep shade of red.

Fish food that contains spirulina, vitamin E, vitamin C, and beta-glucan can change the color of your goldfish.

However, keep in mind, some of these color enhanced foods can affect every color on your goldfish.

So, if you are a goldfish owner who is looking to change the color of your fish, remember color enhancing foods can also affect the white color of your fish, as well as the other colors.

You may not exactly get what you wish for.

Another reason why goldfish lose their markings and change color is due to illness.

Let’s discuss what ailments may be affecting your fish in this way.

Reason #4: Illness And Parasites

A bacterial infection is not that common among goldfish.

It can be a serious condition that is known to affect your little swimmer’s health.

In addition, bacterial infections can make the sharp tones of a goldfish dull, faded, and colorless.

Plus, this type of infection can make a goldfish become sluggish and lose weight.

Let’s talk about each of these now…


Tuberculosis is a serious disease that can affect goldfish. Some of the signs of tuberculosis include the following:

  1. Loss of color.
  2. Tumors that can turn into ulcers.
  3. Extraordinary protruding eyes.
  4. Rapid weight loss.

Tuberculosis can affect the organs of a goldfish. It can be a very dangerous disease that can be fatal.

Skin Flukes

Skin flukes can infect a goldfish and also be the cause of color changes.

How does this work? Skin flukes are small, worm-like creatures that can feed on a goldfish’s skin.

When a goldfish becomes infested by these parasites, the fish will try to fight them off by excreting mucus.

This can cause their color to change.

Some signs of skin flukes include the following:

  1. Lesions,
  2. Clamped fins,
  3. Damaged skin,
  4. Slowness,
  5. Rubbing.

Sometimes an infestation of skin flukes can lead to a bacterial infection, which can cause serious damage to a goldfish.

You can regularly treat your fish with worming medication to prevent these.

Preventing Illness In Your Goldfish

There are some steps you can take to help prevent your goldfish from becoming ill such as

  • Keep your tank clean.
  • Quarantine new fish.
  • Check nitrate and ammonia levels to make sure that they are both adequate and safe.

Water quality also plays a big part in keeping your goldfish healthy, so let’s talk about how you should care for the water that you put in your goldfish tank.

Reason #5: Poor Water Quality

If your goldfish has been losing its color, poor water quality could be the reason.

You can purchase a test kit that will allow you to check the ammonia, nitrate, and pH in your water.

This will help you determine the quality of water in your tank.

Poor water quality can make a goldfish lose its color and become ill.

Poor water to a fish is no different than poor air quality is to us.

It can cause many health issues. So, it is very important to check the quality of water in your tank regularly.


It is important to understand that it is common for a goldfish to lose its black markings and change color.

However, it is just as important to find the reason behind these changes.

It could be genetics, stress, color-enhancing food, an illness, parasites, or poor-quality water flowing around in their tank.

So, don’t jump to the worst scenario.

Take the time to find the reason behind why your goldfish is changing color and losing its markings.

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