Why is my blue betta fish turning red?

In this post, we will answer the question “Why is my blue betta fish turning red?”. We will also discuss the steps you should follow to solve this issue.  

Why is my blue betta fish turning red?

Betta fish are prone to becoming red owing to a combination of hereditary and environmental factors. Betta fish, which are born blue, may naturally change red as they get older, usually around the age of two. However, there have been instances in which betta fish have become red regardless of their age. Ammonia poisoning, a lack of oxygen, and stress are all examples of this.


Some betta fish develop a natural red colouration as they mature. That is typical of blue betta fish, but some betta fish of other colours have been observed to do so as well. The colouration of skin, fins, and eyes are all controlled by the same genes that determine whether a betta will turn red or not. 

Thus, red bettas that turn red will have red eyes and fins as well as the rest of their body. If you have an orange or red betta fish, the likelihood is that it is one of these naturally red bettas. This normally occurs when a child is between the ages of 2 and 3 years old. 

Aside from that, there are certain red betta fish that can change colour without having a naturally red parent. This is because many fish spontaneously change colour during their lives. Clownfish and guppies are two of the most well-known instances of this.

Ammonia poisoning

Ammonia is a sort of toxin that accumulates as a result of an excessive number of nitrifying bacteria and debris. Ammonia poisoning can cause betta fish to become red if they are kept in an aquarium with a high concentration of fish and nitrifying bacteria. 

This is because ammonia burns the betta fish’s gills, causing it to become purple, red, or even bleed in some instances. Other indicators of ammonia poisoning include hazy water and the appearance of sluggishness in the behaviour of the fish. 

As a bonus, you’ll discover that the other fish in your aquarium is also suffering. Some of them may appear deeper in hue, while others will appear paler as time goes on. Some fish will swim at the top of the tank, panting for oxygen, while others will swim at the bottom.

Diseases (Red spot disease, Hemorrhagic septicemia)

Some disorders can cause the colour of red betta fish to change. One of the most prevalent cases is red spot disease, which affects the skin. A fungus known as Aphanomyces invadans is responsible for the development of this illness. Some bacteria, on the other hand, maybe able to do so as well. 

In contrast to what the name implies, the fish will grow red patches rather than turning completely red. On the other side, if the situation becomes severe enough, it can cause fish to become completely pink. As a serious ailment that spreads fast, red spot disease can kill your betta fish within weeks if it is not treated properly. If left untreated, red spot disease can be fatal in as little as two weeks. 

Hemorrhagic Septicemia, often known as Red Pest illness, is another disorder that can occur. That is caused by a bacteria known as Pasteurella multocida, and it is contagious. Other symptoms, in addition to redness, include bloat, irregular swimming, bulging eyes, and gasping for oxygen when breathing. 

Once again, if other fish in the tank are changing colour, you should think that your betta fish is suffering from a sickness that is causing the change. Furthermore, if a sickness develops red patches on the fish’s body, the colour will most likely affect the fish’s entire body rather than just its ends.

Stress (Aggressive tankmates, Lack of oxygen)

As previously said, betta fish change colour as a consequence of a reaction to anything they are experiencing. That includes stress, which can be brought on by a wide range of diverse factors and situations. In the most prominent case, this is demonstrated by the vividly coloured betta fish, which changes colour to red or purple when it is agitated. 

In congested tanks or when the betta fish shares its surroundings with hostile tankmates, such as other betta fish, this behaviour might be observed. The betta fish will change red to indicate to its owner that it is dissatisfied with its surroundings. 

Stress in bettas is also caused by a lack of oxygen. In stagnant water, when there is inadequate water movement in the tank, or when the filter is blocked, you will notice this. Aside from the colour changes, the fish will prefer to congregate in the top areas of the tank since they contain more oxygen.

What should I do if my betta turns red?

If you find that your betta fish’s colour is progressively becoming redder, you should first examine his or her friends. If just the betta turns red, and the rest of the fish seemed to be in good health, this is most likely the result of natural selection and heredity. 

When other fish begin to exhibit concerning signs, you should take the following steps as soon as possible: 

Step 1: Place the betta fish in a quarantine container

First and foremost, I recommend placing the fish in quarantine. This implies that it should not be allowed to come into contact with any other fish for at least seven days, and preferably longer. Because bacterial and fungal illnesses might be infectious, it is important to do so. 

The temperature can then be raised by 1-2 degrees Fahrenheit. This will aid the fish in their battle against any potential illnesses. You may also make use of the API for Aquarium Salt. For every five litres of water, one tablespoon should be added. 

At this time, I recommend that you visit an aquatic veterinarian who can assist you in adjusting the right prescription. It is best not to look for an answer on the internet because this might exacerbate the condition. It’s even better if you have a knowledgeable buddy who also happens to have an aquarium. 

Step 2: Investigate the water parameters

Additionally, you should monitor the original tank for ammonia or nitrite levels, which should be done in addition to the seven-day quarantine. API Aquarium Test Kit is what I use for this purpose. It’s particularly appealing to me because it also tests for pH, nitrates, and nitrites levels. 

If the ammonia level is excessive (over 0.5 parts per million), you should do a partial water change. It is critical, however, not to replenish the water too quickly since the fish have become used to high ammonia concentrations. They will be considerably more stressed if there are significant changes. 

Weekly water replacement should account for 15 to 25 per cent of the total volume of water. You’ll need to figure out how much water is appropriate for your tank. That, on the other hand, is simple since there are no hard and fast laws. Make use of the fish’s natural behaviour as a guide. 

Betta fish prefer a pH between 6.8 to 7.5, which is ideal for them. Maintaining the water temperature within that range will aid your betta in fighting illnesses and avoiding stress. If the water is overly acidic, regular water changes will assist to neutralise the situation. In addition, consider diluting the tank by eliminating the overabundance of tankmates and decorations. 

Step 3: Reduce your level of stress

As previously discussed, a shortage of oxygen can cause stress in your betta fish, resulting in their becoming red. Fortunately, that is a straightforward problem to resolve. Nothing more than placing an air stone in the middle of your tank will do the trick! 

The Hygger Aquarium Air Stone Kit is what I use to help oxygenate my aquarium. This package is one of my favourites since it is simple to use and remarkably silent. The air pump also ensures that a moderately big aquarium receives enough oxygen to complete the oxygen cycle. 

Betta fish tankmates should be kept to an absolute minimum when keeping them in a small aquarium. This is because bettas are quite territorial. As a general guideline, one male betta fish should be kept for every 20 gallons of aquarium water. You should also avoid putting bettas in the same tank as aggressive tankmates, such as cichlids, to prevent stressing them out. 

Step 4: Make necessary adjustments to the temperature

Betta fish demand temperatures ranging from 75 to 80 degrees Fahrenheit. The optimal temperature is near to the temperature of your room in your home. A heater can be placed on top of the tank if the temperature in your room is below 75 degrees Fahrenheit.


In this post, we answered the question “Why is my blue betta fish turning red?”. We also discussed the steps you should follow to solve this issue.  

If you have any thoughts or doubts, feel free to drop us a comment below!

Frequently Asked Questions (FAQs): Why is my blue betta fish turning red?

What does it mean when the colour of a blue betta fish changes to red? 

No doubt that stress is one of the most important factors contributing to the colour changes in betta fish. People’s facial expressions vary under stressful circumstances, such as becoming white as a ghost when scared or wearing a brilliant red face when angry, and your betta fish behaves in a manner that is quite similar to this. 

Is it usual for bettas to alter their colour while they mature? 

Bettas changing colour, as previously said, is very natural, especially if you have a marble betta in your aquarium. But if your betta displays symptoms of illness or stress like lethargy, hiding, or refusing to feed, you should properly examine him to ensure that he is not suffering from anything. 

What are the indicators that your betta fish is dying? 

Other symptoms that a betta fish is ready to die to include discolouration along the fish’s body, such as white or brown blotches, and the presence of parasites. Swimmers with severe swimming ailments may exhibit unusual motions, such as shortening or eating away from their fins. 

What is causing my fish to become red? 

In your fish tank, ammonia levels can rise to dangerously high levels. This is common when a tank is first established or when a large number of new fish are introduced at the same time. Fish with red or purple gills and/or fish struggling for air at the water’s surface are signs of disease. It is possible to lower the ammonium level by using a neutralizer and changing half of the water. 

What is the most difficult to come by betta colour? 

It’s so uncommon that, like pure black bettas, many collectors aren’t even aware that they exist, let alone have seen one. When albino bettas are recorded or put up for sale, keen observers nearly always accurately identify them as transparent, cellophane, or white bettas, depending on their colouration. 

Do betta fish become depressed or lonely? 

Betta fish are territorial by nature and should not be kept in the same tank like any other betta fish since they will fight and hurt each other, which will frequently result in death. If they are in a large tank, they are unlikely to feel lonely; yet, they may become bored if their tank is too small.


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