Why Your Fish Is Losing Color?

By Nadine Oraby | 2020 Update

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Why do fish lose their color and what to do about it? This article will answer these questions that often perplex concerned pet fish owners.

So, why do fish lose their color? There are a plethora of reasons why this might happen:

  • Stress
  • Change in environment
  • Diseases
  • Poor diet
  • Genetics

While fishes losing their striking colors is unfortunate, it’s not a permanent change. You can bring your fishes back to their former glory by taking a few measures such as:

  • Regulate the aquarium environment
  • Contact a veterinarian
  • Healthy fish diet
  • Suitable tankmates

Keep reading, so you find more insights regarding the causes of fish discoloration, and how to prevent it, so yours doesn’t suffer.

Why do Goldfish change colors (Video)

Leading causes of discoloration

There are a lot of factors that cause fish to lose color, but there is one, which stands out as the most common reason of all.


It is easy to say that stress is the leading cause of discoloration in fish but it is more important to identify the factors of stress. It is mainly caused when the living conditions and environment are not fit for the fish. For instance:

  • Water pH levels
  • Amount of water
  • The purity level of water

The abovementioned factors are the most common reasons that lead to stress in a fish. Other elements such as the size of the aquarium, type of tank mates, nutrients in water and lighting conditions will also have a positive or negative impact.

Proper lighting conditions in the surrounding can go a long way in reducing the stress levels in fish. Moreover, fish thrive in a specific water temperature. Therefore, variations in water temperature will also lead to stress and discoloration. However, not all is gone as the fish may regain its color once it adapts to the new environment or the environmental conditions are made suitable according to its requirements.

Poor diet

Sadly, people are usually unaware of the diet and nutritional requirements of fish. This is mainly due to the lack of research and awareness about it. They assume that the processed fish food available in the supermarkets is a sufficient diet for their fish. Hence, they think that fish require little maintenance and are easy to keep.

However, this is not the truth. Commercial flake foods lack some essential nutrients many fish need. They are ‘standardized’ fish food and can’t be relied upon alone as a wholesome diet for every fish. They also lack color enhancing elements in them which initially causes discoloration. Commercial fish food has also been reported to cause ‘burning’ in fish forming dark patches on them.

Low-quality food has been known to make fish prone to illness. This study reveals that poor quality fish food can lead to malnutrition. Sometimes, fish may become so weak that they can’t fight infections.

More reasons for discoloration

In addition, fish can also suffer from color loss due to some undiagnosed disease. Bacterial diseases and tuberculosis can cause discoloration in fishes. Loss of color is just one symptom. Other symptoms include weight loss, signs of fatigue, abnormally bulging eyes, etc.

Common diseases that cause discoloration:

Columnaris: Columnaris is a bacterial infection found in fish causing white spots on the surface. It also causes fraying fins and sores on the body.

Anchor Worms: Anchor worms are small white worms. They cause lethargic behavior, rubbing, scraping, sores, discoloration, and breathing difficulties in fish.

Ich (White Spot Disease): Ich is caused when the parasite starts feeding on its host; the fish. It causes white spots to appear. It also causes abnormal eating behavior in fish.


Some fish are prone to lose their color, while others become more vibrant as they age. And some fish keep changing their color over a specific time period.

For instance, Bettas keep changing their color over their lifetime. And they can get really dull during some phases. Goldfish change colors in the first year of their life as well. In fact, they might experience slight changes in color until they have matured fully and started breeding. Young goldfish usually mimic the color of either of their parents. Black goldfish usually lose their color to dark grey as they grow old.

Moreover, some fish such as Kribensis become more vibrant during mating season to attract a partner. Male fish usually become more colorful at the beginning of the breeding season to attract mates. Female fish, on the other hand, become more vibrant while laying eggs. Such fish lose color after the breeding seasons ends and don’t regain it until the next one.

Because of its hereditary nature, genetic discoloration can’t be controlled by human behavior. Hence, one shouldn’t get frustrated if their fish lose color due to genes or over a specific time period.

How does a change in the environment cause discoloration in fish?

Fish are highly sensitive to their environment. Inadequate lighting causes fishes such as goldfish and koi to lose color. This is because they require adequate exposure to sunlight so the pigment in their skin brightens their color. Having access to enough UV rays is crucial. This study shows the importance of light on marine angelfish, as a proof of concept. Additionally, change in water type and chemical composition such as adding excessive nitrates and phosphates also causes discoloration in fish.

Fishes such as the Shoaling fish require other fish companions. If they are left alone, they will lose their color. It goes without saying that the cleanliness of water will also impact a fish’s color. If it is left unchecked and dirty the fish will abnormally lighten or darken its color.

How to maintain fish color

There are a lot of measures which can be taken to prevent discoloration in fish or to restore their color. They are easy to implement once the root cause is identified.

Regulate the aquarium environment

The environment plays a key role in keeping fish healthy. The following must be done to ensure the aquarium environment is favorable for the fish:

  • The water pH level must be neutral (maintained at 7)
  • Regular water changes every 2 weeks
  • Effective water filter
  • Tank size must be sufficiently large
  • Water temperature must be regulated at all times. Use heater if needed
  • Ammonia, nitrite and nitrate level should be at zero
  • Sufficient exposure to sunlight or adopt UVB light source

Keep suitable fish mates

Some fish are more social than others. Shoaling fish such as goldfish are at their best when they have other fish living with them. Living alone stresses them out, which leads to discoloration. Other fish such as barbs, danios, guppies, and tetras should also be kept in schools. Don’t keep any aggressive fish, such as betta fish, in a community tank. They will be a source of stress for their fish mates.

Monitor the aquarium for any signs of fights among fish. Look for broken fins rather than fraying ones as it is a clear indicator of a fight. Sometimes fish also become aggressive with each other because there are too many of them in the aquarium. Therefore, allow sufficient space for fish by not overcrowding the aquarium.

Contact a veterinarian

If you see symptoms such as weight loss and fatigue along with discoloration, then getting the fish checked from the vet is necessary. Your fish could be suffering from an undiagnosed disease. Also, examine that the fins are erect and white to check for symptoms. The eating behavior of fish also tells a lot about their health. So, if you notice abnormal patterns, it is best to get the fish checked from the vet.

Moreover, If you see spots, rashes, fraying fins, or any other kind of abnormality in your fish, then consult a specialist as soon as possible.

How does diet help in maintaining fish color?

Diet is the most important factor for fish health and appearance. They must be given a well-balanced diet with proper nutrients as well as color enhancing foods. They must be fed vegetables, fruits, herbs, protein, seaweeds, and commercial color improving foods. Only feeding processed commercial food to fish can cause discoloration.

Following are the most effective color enhancing foods:

  • Bell peppers
  • Plankton
  • Mysis shrimp
  • Kale
  • Swiss chard
  • Krill
  • Saffron
  • Blueberries
  • Cantaloupe
  • Green seaweed
  • Paprika
  • Rosehip
  • Scallops

Crustaceans such as krill and Mysis shrimp are really good color enhancers. Scallops and fish are ideal for carnivorous fish. There are also frozen foods rich in vitamins.

On the other hand, vegetables best preserve their nutritional value when they are fresh. Spinach, broccoli, and romaine lettuce must be fed to fish in order to make them brighter and vibrant. Moreover, great care must be taken while purchasing commercial fish food. One must look at the ingredients to ensure that it has high nutritional value instead of filler ingredients. Omega-three fatty acids, vitamins, and carotenoids must be present. These ingredients are essential for your fish and aren’t easily found in a natural diet. Lastly, you could also soak the fish food in additives which increase its nutritional value.


While we’ve discussed most of everything related to the subject at hand, there are some commonly asked questions that should be addressed.

What to do if fish are fighting?

If you buy a species of fish that are naturally aggressive such as Beta fish and tiger barbs then get other fish in the aquarium who are equally aggressive too. They won’t fight with each other because they will fear the other party hurting them back. Make sure you don’t overstock the tank though.

Another effective tip is to redecorate your aquarium. Turn off the lights of the aquarium and rearrange the aquarium setting and equipment so fish can’t recognize their ‘territory’ or ‘spot’. This will make them a lot less territorial, and reduce their aggression levels.

Creating more hiding spots are also likely to reduce fights among fish. This can be done by adding live plants, plastic décor with passable areas and placing equipment in such a way that it allows fish to hide.

Why do fish chase other fish?

Fish chase each other for 4 main reasons:

Coupling: This is the major reason why fish chase each other. It will be usually seen that a couple of fish will be swimming faster than the other group. There is no need to worry about it since it is normal.

Incompatibility: Fish don’t get along with all other fish, so some are their friends and some are enemies. Some fish are more dominant than others. This makes them more aggressive towards shy and submissive fish.

Competition for fish: As Darwin’s theory talks about ‘survival of the fittest’ which involves competing with others, this behavior can also be seen in fish too. If some fish are left hungry, they start chasing the ones with food.

Territoriality: Fish create their own territories in the aquarium by chasing away other fish. This is usually due to overstocking in the aquarium.

What causes cichlids to lose color?

Cichlids lose color when water pH is not maintained at 7 and ammonia level is above 0. Cichlids are aggressive and bully other fish which causes stress leading to discoloration. They also lose color as they grow older. For instance, if they are initially bright yellow and then change their color to orange as they age, then it is perfectly normal. Moreover, Cichlids may lose color after the breeding season is over.

And like all other fish, if they are not fed a proper healthy diet, they will start to lose color. Therefore, their diet should contain frozen shrimp, pellet foods, Beta carotene, spinach, beans, cucumber, etc.

How can you prevent fish from losing their color?

Diet and environment play a key role in maintaining fish color. Fish must be comfortable and happy in their environment to show vibrant colors. They must have a properly maintained tank with the right water composition and temperature. Filtration system must also be proper with the filter being replaced every month. The water should also be changed every two weeks.

Other factors include:

  • Proper lighting conditions with exposure to ample Ultra Violet rays.
  • Suitable tankmates
  • Diet must include carbs, fats, protein, vitamins, and minerals.

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