Why do Discus Fish Change Color?

There are various reasons why discus fish change their body color. Even a slight change in water parameters can cause your discus fish to change its coloration, but other factors such as stress, diet, age, or disease will affect their bright colors.

For the Discus fish, it is an everyday thing to change its color. This species has developed this trait during its evolution. Its purpose of it is simply to blend into its environment, making it harder for other species to see him in the water.

This is why they change their color in general, but let’s delve a bit more into this phenomenon!

Reasons Why Discus Change Color

If you densely plant your aquarium, then your Discus is eventually going to adapt to the environment by changing colors. It is how they naturally react and there is nothing to worry about when it comes to this reaction. There are other factors, however, that are a bit more concerning.

When your Discus suddenly changes its color, it is more likely that he feels stressed or frightened. These are the things you can and should do something about. They signal that there is something wrong in the aquarium.

Now we are going to help you by describing all the factors that can cause your Discus to change its colors so that you know what to do about them.

1. Stress

In fact, stress is by far the most common reason for this species to change its colors. A stressful environment can not only result in color change but in the weakening of the immune system as well. The two things that cause the most stress are water changes and environmental changes.

When you suddenly put your Discus into a new tank, he is going to be stressed out a bit until he gets used to it. That is when you are going to see him change his colors. Stress also comes with loss of appetite, which makes your pet even more vulnerable to diseases.

2. Water Parameters

Like other species, the Discus fish also has its specific requirements when it comes to water conditions. They are especially sensitive to pH and temperature changes. Although the water in the tank has to be changed on a regular basis, it also changes these two parameters.

Until the pH and temperature get back to normal, your fish is probably going to change its color. We encourage you to monitor both of these parameters regularly so that your pet won’t get stressed out. Discus require a stable environment with constant 82-86 degrees Fahrenheit and 6.0-7.0 pH.

3. Diet

Another reason for Discus to change their colors is if there is not enough protein in their diet. This is definitely something to think about if you notice that the colors of your pet have changed. Try to introduce more protein-rich foods into their diet and see what happens.

In general, the ideal diet for the Discus should be mainly based on protein. It should also be a diverse diet that contains enough vitamins, fibers and minerals besides protein. Simply put, you should aim to mix a range of high-quality foods together and feed it to them throughout the day.

4. Disease

A common disease that can cause Discus to change its colors is Ichthyophthirius or Ich, as people simply call it. If you notice big white spots on its body, then your fish most certainly suffers from this disease. It is a parasitic disease caused by a parasite called Protozoan.

The white spots you can observe are all individual parasites that got attached to the body of your little pet. The more parasites there are in the tank, the worse this condition is going to get. Keep your fish on a good diet and keep the water parameters ideal.

This disease can only affect your Discus if it’s weak due to stress or another disease.

5. Age

Once your Discus fish reaches 5-6 years of age, you might notice that his colors are especially vibrant. That is when this species reaches its peak when it comes to its colors. This works contrary to what people usually expect.

What you would expect is its colors to fade as the fish gets older. In fact, the younger the Discus, the less intense its colors are. This doesn’t mean that your fish is sick or anything. It only means that it’s too young for its colors to fully develop.

A few years after birth, however, they start to look significantly more colorful than before.

Why do Discus Change Color When Scared?

Discus are peaceful fish that prefer a calm environment. You need to set up a tank for them that is as safe and comfortable as possible. Also, don’t place the aquarium in a hectic room where people or other pets frequently go near the tank.

Even rapid-moving shadows can scare a Discus fish. When they feel frightened, they are going to change colors. They can consistently maintain their colors but only in relaxing environments. You shouldn’t install strong lighting on the tank either.

It has to be on the dimmer side, which contributes to a calmer environment.

How to Enhance Discus Fish Color?

The most effective way to enhance their colors is to feed them a variety of healthy foods. These include glass worms, algae, vegetables, blood worms, beef heart and blood worms. You need to combine these in order to maximize the effect.

Since Discus absolutely love these foods, they are going to be more than happy to eat them. Furthermore, make sure to control ammonia levels and to avoid chlorine altogether at all times.

The color of your discus fish can also be enhanced by keeping a bigger school together. If they feel safe, their colors will be more vibrant and prominent.

When Will Young Discus Fish Color Up?

Don’t be surprised about young Discus fish not being as colorful when young. They need a couple of years until they start to flourish in their beautiful colors. There is nothing you can do about it except be patient and waiting for it all out.

Around 5-6 years of age is when they reach their peak when it comes to their colors.

Why do Discus Fish Color Fade After Water Changes?

Discus fish will fade their colors after a water change because they are very sensitive to even the smallest change in water parameters. Bigger water changes can cause stress to discus fish, and as a result, their color will start fading.

You shouldn’t worry about your fish losing their color, because once they get used to the slightly different water conditions, they will regain their colors. Frequent water changes are important for them, so don’t skip any, even if your fish will get discolored for a few hours.

Why My Discus Fish is Turning Dark or Black?

If your Discus fish turn black it is a bad sign. Most of the time, discus fish will turn dark when they are infected with fungi, parasites,s or bacteria. Extreme stress can also cause discus fish to change their color into darker tones, or even black.

In rare cases, they are simply adapting to their environment. Most of the abovementioned issues are the result of stress which makes the Discus vulnerable to infections. If you notice your fish turning dark, contact the vet for advice immediately.


Discus fish are sensitive and they can be easily stressed out. As a result, their colors can fade, which is when you should just give them some time to recover. There are other instances where you need to take a closer look at the problem.

Diseases, dirty water and inaccurate water parameters can all weaken their immune system and cause stress for them. If you notice that your Discus has changed its color and didn’t recover after a while, then you need to treat him yourself or contact your veterinarian.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

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