Why Do Oscar Fish Change Color? Can You Improve it?

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Oscars are among my favorite type of fish. That is somewhat because their intense colors bring plenty of life to the tank. Yet, once in a while, I noticed that my Oscar fish begin changing their colors. Since this phenomenon got me worried, I started researching the topic a bit deeper.

Oscar fish change color mostly as a result of natural aging; as they grow older, the Oscars typically present faded colors. However, discoloration may also occur once the Oscar is under stress – mainly when the temperature pH and toxins are outside the desired range. 

As we move forward, I will show you how to prevent Oscar fish from changing their colors. That is particularly valid once the situation is reversible. Also, I’ll provide you with a few useful techniques to enhance the colors of your Oscars, especially if they appear too pale.

What Makes Oscar Fish Change Color?

People love Oscar fish because they are beautiful and colorful. However, it often comes as a shock to aquarists when those colors begin to change. But this shouldn’t always concern you. First of all, you should note that it is natural for Oscars to change color.

Secondly, you need to realize that those changes can be positive or negative. That is to say, an Oscar fish’s colors can either improve or deteriorate. Naturally, anyone with fish would prefer an improvement rather than deterioration.

Fortunately, there are ways to either prevent these negative changes or to reverse them. But you can only take such steps if you know the reasons your Oscar’s colors have changed in the first place. These reasons typically include one or more of the following:

1. Age-Related Changes

That is the most common reason why Oscars change color. If your fish were young when they arrived, you probably noticed that their colors were dull, especially during the fry stage. But as they grew, those colors became brighter and more intense.[1] 

This happens with most Oscar fish. Some of them will even develop stripes and patterns. This transformation is gradual, but you can see it if you make close observations. However, as they grow older, their colors will either fade or become less pronounced. The intensity of this change will depend on the Oscar.

In other words, your Oscar will feature pale colors at the beginning of its life, and towards the end of the road. Since the average domesticated Oscar will live approximately 8-12 years,[2] at the age of 6-7, it may show less intense colors. That is a natural, healthy process.

Also Read: Why Is My Oscar Fish Turning White?

2. Inappropriate Water Conditions

Color changes resulting from your Oscar’s mental state are sometimes challenging to read because Oscars don’t always respond the same way when exposed to stress. Yet, things are somewhat simpler where the water conditions are concerned. 

All Oscar fish require specific water parameters. They need a temperature ranging from 74 to 81 degrees F and a pH ranging from 6 to 8.[3] Also, you must control the ammonia, nitrate, and nitrite levels in the water.

It is worth checking the API FRESHWATER MASTER TEST (link to Amazon). That efficient bundle will help you to estimate the current pH, nitrites, nitrates, and ammonia in your tank. If you’ve concluded that one of these parameters is too high, you should replace the water more frequently.

A failure to do so will cause discomfort in your Oscar fish. It will generate stress and leave them vulnerable to diseases. This will also make their colors fade. The brighter the colors, the healthier the Oscar. The paler the colors, the sicker the Oscars. 

3. Stressful Conditions

Stress is another common cause of color changes in Oscars. Happy Oscars are relatively dark in color. Once stress enters the picture, those colors will grow brighter. Sadness also makes them pale. However, this doesn’t apply to every single Oscar.

It is merely the trend that has been observed in most Oscars. But this works in your favor. That is to say, the fact that Oscars can change their colors means that you can read their mood by observing these transitions.

Of all the factors that can alter the color, stress is the most powerful. If your fish are being bullied or going hungry or they are shocked from the process of being added to the tank without proper acclimation, their colors will undergo significant changes.

Again, it is worth reiterating that the changes are not necessarily the same for each Oscar. You cannot use the changes you have noticed in one Oscar to reach conclusions regarding the changes you have seen in the other. Observe each individual Oscar until you learn to discern its patterns.

Also Read: Stress In Oscar Fish

4. Diseases

Ich is a disease with parasitic origins.[4] If your Oscar has the condition, it will turn a whitish color. In some cases, it will only develop white spots. If your fish is turning pale or developing white spots, you can conclude that it has Ich.

If it isn’t Ich, ‘Hole in the Head’ disease is probably the cause. This condition typically results in a concentration of spots around the eyes and mouth. You should also watch out for rotting on the tail and fins. 

No one has definitively identified the cause of ‘Hole in the Head’ disease, though some people have blamed it on a Vitamin C deficiency, overcrowding, poor nutrition, etc. Whichever the reason might be, the video above will help you treat it.

Also Read: 17 Oscar Fish Diseases

How to Keep Oscars From Changing Their Colors?

There are ways to keep your Oscars from changing their colors. These may come handy if your fish become too pale, and the underlying cause is reversible. Keep in mind that those solutions won’t work if the issue is age-related.

The key is to give your Oscars all the care and resources they need to maintain their health and comfort. You can use the following methods:

1. Feed Them Properly

An inadequate diet will cause stress and illness in Oscar fish. And as you might have guessed, pressure and disease will cause changes in color to occur. It isn’t enough to satisfy your Oscar’s hunger. You should also feed it nutritious meals. 

Commercial flakes and pellets are a decent starting point. But you cannot rely on them to meet your Oscar’s nutritional needs. You should add a variety of living, frozen, and freeze-dried foods to the mix.[5] This will give the Oscar the nutrients required to maintain its coloration.

Also Read: How To Feed Oscar Fish

2. Ensure High Water Quality

Try to maintain a pristine tank. Measure the temperature, pH, ammonia, nitrate, and nitrite levels regularly to ensure that all these parameters are within the appropriate range. Also, ensure that your filter is powerful enough to keep the tank clean.

Don’t forget to remove all the dead organic matter in the tank, including fish and plants. Comb the substrate for waste and uneaten food before it rots and introduces toxins to the water. Lastly, regular water changes cannot be emphasized enough.

If you can keep the water within the appropriate range of parameters, you will give your Oscars the conducive environment they need to live healthy and happy lives. Satisfied Oscars are more likely to feature sustainably bright and attractive colors. 

3. Avoid Overcrowding

You should, by all means, avoid overcrowding. Keep your Oscars in tanks of at least 75 gallons and try not to overstock them. You should also note that Oscars do better when they live singly. That is because they are relatively large fish with aggressive personalities. 

Though, they can live with other fish if you find them suitable tankmates such as other cichlids of similar size. Avoid larger companions that are strong enough to bully your Oscars. A healthy and happy Oscar is one that has all the space it needs to swim freely in the tank. 

A thrilled Oscar is also one that doesn’t have to contend with bullies and predators on a daily basis. If you can’t afford to replace aggressive tankmates with more peaceful ones, add plants and decorations to the tank. Give your Oscars hiding places that they can use to find a modicum of peace.

Some people argue that lighting can impact a fish’s ability to change its color. But there is no substantial evidence to prove this theory. Lights that are too strong and bright can cause stress in your fish. But the colors will change primarily because of the pressure, not the lighting. 

Also Read: Oscar Fish Tank Size

How Can I Improve My Oscar Fish Color?

You can improve the colors of your Oscar fish by following these three steps:

  1. Feed them nutritious meals that contain brine shrimp, vegetables, and freeze-dried foods.
  2. Put a blackened background and use contrast lightning.
  3. Consider artificial coloring, such as bright fluorescent dyes.

If your Oscars are not as beautiful as you would like, you don’t have to wait for them to change their colors naturally. You can take steps to enhance this process. But there is no way to guarantee success. 

The results you will acquire will also vary depending on your expertise and the attributes of your Oscars. However, if you are determined to experiment, here is an elaboration for the mentioned steps above:

1. Choose the Right Diet

It is known that a poor diet will destroy your Oscar’s coloration. However, a proper one will do the opposite. Some food items have a reputation for enhancing coloration in fish. They include crustaceans like brine shrimp, freeze-dried foods like krill, fresh vegetables like spinach and romaine lettuce, and peas, to mention but a few. 

Yet, you cannot apply the same diets to all fish. Some foods do a better job of enhancing color in some fish than others. Your best choice is to ask your local fish store for the color-enhancing diet that can work on Oscars.

For example, some popular options include Hikari pellets and Optimum Hi-Pro Koi Food. You should also try insects like crickets and cockroaches. Do this occasionally, not regularly. Consult a professional to identify the insects that are not poisonous to an Oscar. 

However, keep in mind that most professionals will encourage you to avoid insects that have been exposed to insecticides. These could have a negative effect and are very likely to be toxic to your fish. 

Also Read: What Do Oscar Fish Eat?

2. Adjust Your Lighting And Background

While lighting cannot change the color of your Oscars, it can enhance them. Actually, if you can find bulbs with contrasting colors, their combination with your Oscar’s scales will produce a noticeable change. 

Naturally, that transformation isn’t real. It is merely a trick of the light, and it will disappear once you change the lighting. But it is relatively commonplace for people to enhance the appearance of their Oscars by adding the right lighting.

Another way to intensify the appearance of pale Oscars is by adding a dark background to your tank. That also includes the substrate. As with the lighting, this won’t change the colors of your fish. But it will make them pop.

3. Dyed Oscars

Some fish stores dye their fish. They dip them in a colored dye that the Oscar fish’s skin will eventually absorb.[6] This is done in situations where people want to produce colors that cannot be created through selective breeding. 

While dyeing can produce exotic colors, it is highly discouraged because it is cruel. The process is painful for the Oscars. For that reason, I highly recommend avoiding this option. However, keep in mind that the Oscars you’ve bought may have gone through this process.


Most of the time, Oscars change their colors due to natural aging. As they grow older from their larva stages, their colors will gradually intensify. On the contrary, towards their final years, their bright colors will eventually fade.

However, that particular discoloration could also be as a result of stress. The first approach you should take is examining your water. Measure the temperature, pH, and toxins levels and ensure that they are within the appropriate rage.


  1. https://mrfishkeeper.com/color-changing-fish/
  2. https://www.fishkeepingworld.com/oscar-fish/
  3. https://modestfish.com/oscar-fish-care/
  4. http://www.tfhmagazine.com/details/articles/preventing-ich-full-article.htm
  5. https://www.ratemyfishtank.com/blog/improving-color-in-aquarium-fish
  6. https://aquariawise.com/oscar-fish-care-guide