Do Rainbow Sharks Change Color? 5 reasons why your Rainbow Shark is losing color

Do Rainbow Sharks Change Color

One of the problems people face in fish keeping, especially newcomers, is their fish changing colors. For instance, you bought a blue fish and keep him in your aquarium, then in a few months or years, the fish will lose or change color to black etc. When this happens, you will be surprised and alarmed too, probably because you think there is something wrong with your fish, well, indeed there is something wrong, so In this article, we will look at the reasons why Rainbow sharks actually change or lose color.

Rainbow Sharks, with their vibrant colors and dorsal fin resemblance to true sharks, add an intriguing facet to freshwater aquariums. While their name might suggest a connection to Chondrichthyes, it’s essential to recognize their actual classification in the Actinopterygii order. The glow-in-the-dark variant, though genetically modified and fascinating, further underscores the symbolic use of the term “shark.”

Do Rainbow Sharks Change Color? Yes, Rainbow Sharks and other fish can change color due to some reasons such as stress and aging. Some causes of stress are wrong water parameters, disturbance from unsuitable tank mates and changing or water.

Do Rainbow Sharks Change Color

Indeed Rainbow sharks can actually change or lose color, but it doesn’t just happen.

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There are factors that drives fish to lose or change color, which we will look at in a moment.

Although we understand that there are some fish and other aquarium animals that could naturally change color to match with their immediate environment.

But when it comes to rainbow sharks and some other fish, they don’t just change color to match their environment or anything like such, they change or lose their former color for reasons such as.

Why my rainbow shark is losing color

Why Rainbow Sharks Change or Lose Color?

Some common proven reasons why rainbow sharks change their former color to another are:


Every animal, including human beings, has their lifespan and when their life span is coming to an end, they they will start changing from their former self to something different.

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This is very applicable to all fish, which rainbow shark is inclusive.

Generally, the lifespan of a rainbow shark is 8 years.

When they approach their age limit, then their color will change from their former color to another color or it might start fading away thereby losing color.

So if your rainbow sharks or any other fish are changing color, them you might have to look at their age and see if they’re approaching their age lifespan, if they’re, then there is absolutely nothing you can do about it.


Another reason your rainbow shark is changing or losing color is probably because it has some infections or diseases.

Related: Can Sunfish live in a tank with Cichlid?

There are some diseases that might change your fish from the former color you know it with to another thing different or from thick color to more lighter color etc.

When this happens, the only remedy you have is to try and get the attention and advice of a veterinarian doctor, and if possible for proper medication.

So your rainbow shark might be losing color because it is sick and needs a medical care from a vet.


Many times, environment contributes alot to fish lose of color.

This is because fish, just like some other aquarium animals are very sensitive to their environment and how it changes.

Related: Do Rainbow sharks get along with Neon Tetras?

Let’s say you got a rainbow shark that was gotten from the wild and has lived all it’s life in the open water with enough sunlight.

Then you put it in an aquarium with a lesser amount of sunshine.

Don’t be surprised if it starts losing it’s former color due to change of environment etc.

So if your rainbow shark is losing color, you might consider bringing in a light to your aquarium.

There are many good aquarium lights that you can use on your rainbow shark tank.


The most common reason why rainbow sharks and so many other fish lose their former color is due to stress.

Fish are very vulnerable to stress, especially fish like rainbow sharks.

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Although they are an agent of stress, but generally, they don’t like getting stressed themselves.

There are many ways a fish could get street, which are:

Having unsuitable tank mates: This is why it is very important to keep a suitable tank mate for your fish and other animals because when they have a hostile mate, then they will always fight, chase each other around, and even drag everything, including territories and foods.

So having an unsuitable tank mate is very problematic and could cause problems for your pets which could include a change of color.

Change of Water:

Another great agent of stress is a change of water.

Rainbow sharks and many other fish do not like disturbances like frequent changes of water and disturbing their water.

Generally some fish love living in calm water without much water current.

So changing of water or disturbing their water could be a great disturbance to them, which could bring about stress and maybe loss of color.

Wrong water parameters:

Wrong water parameters are responsible for more than 60% of stress in fish.

Every aquatic animal has its own suitable water parameters, such as pH, water type, temperature etc.

Rainbow Sharks have it’s own water parameters, such as being a fresh and calm water dweller, pH 6.0-80, temperature 70-80, water hardiness 7-8dh.

Other things that causes stress to fish are chemical level in the tank such as nitrate and ammonia.

On a normal basis, these chemicals should be 0% in your tank because they are very harmful to every living thing, including your rainbow sharks etc.

So if your rainbow shark starts losing or changing color as the case may be, then you might have to check if they are getting stressed from anything and adjust it to reduce their stress level.

Tank size:

Tank size too could lead to stress for rainbow sharks.

We all know that this fish normally gets big when they fully grow, and keeping them in a tank where they won’t feel totally comfortable and swim about could bring about stress, which could in turn lead to lose of color and aggression.

Tank size matters alot, so getting big, good and suitable tanks for your fish is the ideal in keeping a happy and less stressed fish.

A fully grown rainbow shark should need up to a 75 gallons tank to be able to swim about freely.

Also air pump, filter and heater matters alot for free flow of oxygen, water and heat in the tank for your shark to be comfortable.

Poor Diet

As the saying goes ” we are what we eat” This is true, not only for human, but for animals too.

The fact is, your shark might be losing it’s natural color to something else because it is lacking the quality food it’s body needs to run effectively and stay healthy.

Malnutrition can change the color of animals, so your rainbow shark might be lacking those nutrients the body needs to be healthy.

If your rainbow shark is changing color, then you might have to look at the type of food you give it.

So to help you more, there are some color enhancing foods for fish

Some of the most popular color enhancing foods are:

  • Kale.
  • Paprika.
  • Saffron.
  • Krill.
  • Plankton.
  • Green seaweed.
  • Swiss chard.
  • Blueberries.
  • Cantaloupe.
  • Bell peppers.

What Color Are Rainbow Sharks?

Talking about rainbow sharks and change or lose of color, you might want to know what color they are known for.

What color are rainbow sharks? The rainbow shark has an elongated black, bright blue or dark blue body. Their fins has red to orange red color and the abdominal is flat.

The above mentioned are the natural colors of rainbow sharks.

But sometimes, the above mentioned factors could contribute to the change or fading away of these colors to some other colors you might not think of etc.

So these are the true colors of Rainbow Sharks.

Red Tail Shark Turning Grey

Red tail shark popularly referred to as rainbow sharks could sometimes turn or change to other colors including grey.

Red tail shark could turn to grey because of stress or aging. Stress or aging are the two most common factors responsible for the change of color of this fish.

So if your red tail shark or rainbow shark is turning grey, then check my above explanations and follow my procedures or better call a vet to look into it.

Infact I would definitely advise you to always get a vet anytime your pet starts behaving abnormal etc.

Why Is My Rainbow Shark Turning White?

Naturally, fish do lose or change colour as the case might be, but this just doesn’t happen. As I mentioned above, there is some factor responsible for this.

Why is my rainbow shark turning white? Your rainbow shark might be turning white because it is old or it is stressed. Stressing could be caused by many factors such as wrong water parameters, unsuitable tank mates, and poor feeding.

One of the problems fish have is getting stressed easily.

When they do, they may naturally change in many ways, both in behavior, and physically on their body which includes change of color.

Stress can make rainbow shark become aggressive and lose their appetite etc.


These are some of the common factors that could easily make a rainbow shark to lose color.

As always, if you notice anything strange with your pets, please do well to contact a qualified veterinarian doctor to look into it for best medical advice and possible medications.