Last Updated on September 28, 2021 by Woody Pet

What Is Betta Fish Tumor?

If you keep fish at your home, you are most likely familiar with some of the types of diseases they can be afflicted with. This is not a rare occurrence and many of the fish owners are dealing with it. However, if your Betta fish, which are special and high maintenance already, are suffering from an illness, it must be painful and sorrowful to deal with. This special friend that you keep in your tank, you provide him with a great deal of attention, is sick, and you desperately want to help him, or her.

In this article we will particularly detect the types of Betta fish tumor, and help you to prevent them, as well as to recognize them, so that you react properly.  We know that the very term “tumor” brings you a great deal of alarm and terror already, but do not lose hope. It is not always that dangerous.

Let us first get into the matter of which factors influence the emergence of tumors and why these dangerous opponents exist to begin with.

Where are the betta fish tumor coming from?

First of all, like we humans have predispositions for different sorts of cancers, so do the Betta fish. Mainly, their genetic characteristics are the reason for getting tumors. In these cases, there is not much one can do to prevent the deadly silent enemy.

When we take into consideration the Bettas with healthy disposition, a lot of things depend on you as an owner. One must keep their tank with clean water, and feed them regularly and properly, in order to keep them healthy. Otherwise, there are tumors that can show up if the owner is irresponsible and doesn’t fulfil the obligations owed to the Betta fish pet. 

Viral infections are a potential threat to your Betta fish when you add some new companions of a different species in their tank.

Detection of Tumor in Betta Fish

Betta Fish Tumor

Less dangerous types of tumors a Betta fish can have are those which are manifested by lumps and swellings on their skin, or under the skin. Tumors differ in their size. Some tumors can be large and others may be small. 

If you notice that a tumor has taken over all of the Betta fish’s skin, you should know that this type of tumor is creating difficulties for your Betta in their swimming and floating in the aquarium. 

Anyways, regarding the lumps that you may notice on your Betta fish’s skin, do not get into an outright panic. There is actually a small chance that the lump is a cancerous tumor.

The lumps have bigger odds to be proven to be a betta abscess, or a betta fish ulcer. Also, lumps can be a manifestation of water retention, constipation, or a swim bladder disorder. 

Worst kinds of tumors are those that are internal and can not be detected only by your bare eyes. This is because they seriously affect the Betta’s swimming and diet, which is, unfortunately, a pretty hopeless situation. With these types of tumors, we recommend that you put your Betta fish out of misery by an euthanasia. That is the final good and merciful act you can do for your fish.

The painful truth is that there doesn’t exist a cure for Betta fish tumor. 

If, however, their swimming is not too much affected, you should let them live. As their owner, you can judge whether their life quality is worth it. They should not suffer if they can not live a substantial life anymore. 

Detect Tumor on Betta Fish by Their Location

In order to distinguish which lumps can represent tumors, the key lies in the location. Depending on the particular place of the Betta’s body where the lump can be found, you can determine the possibility whether that lump represents cancer, or some other health issue for your pet. 

Can There be a betta fish tumor on head?

Yes, there is a possibility that Bettas can suffer from a head tumor. Also, as we mentioned, not every lump is a tumor, so more likely, the lumps you notice on the head are infections caused by bacteria. Bear in mind, these infections are also dangerous and should be treated properly. Tumors are not the only imminent danger to your Betta fish. 

Betta Fish Tumor on Stomach

Your Betta’s stomach is often the location where cancerous tumors can be found. Other than that, the lumps on the stomach can mean infections, constipation, or swim bladder disorder. 

Betta Fish Tumor on Side 

Located on your Betta’s side, a lump can be recognized and diagnosed as a tumor. Besides that, it’s possible to be caused by bacteria, swim bladder disorder, or dropsy.

Also, a lump in the Betta fish’s respiratory organs, the gills, may be a sign of tumor. 


We already pointed out some of the Bettas are unfortunately genetically predisposed to suffer from tumors. 

However, there are many things you can do preemptively, in order to avoid such a big threat to the health of your Betta pet. 

Keep the water in the aquarium clean. You should regularly replace one quarter of the water weekly, so that it doesn’t catch bacteria that can hurt the Betta.

Do not be cheap on food. Betta fish need protein in order to survive. If you buy cheaper food that does not have protein, it can damage your Betta fish’s health.

Do not buy inbred Bettas. They are prone to health complications, and one of them is exactly a potential tumor.  


We covered a lot of potential threats to the well – being of your favourite pet that is the Betta fish. While many times you can mistake the lumps and bumps with cancerous tumor, more often than not, it is shown that you should not jump to conclusions and think of the worst.

However, you should pay attention to the physical appearance of your Betta in order to detect lumps. That way, you can further find out whether the danger is real or is only benign. 

Also, we suggest that you should not tread lightly the other health issues of your Betta that are manifesting themselves through those lumps and bumps – such as constipation, swim bladder disorder, or bacteria. 

If you want to prevent tumors in your Betta, you simply have to follow the instructions that keep them safe and healthy from any other setbacks. These steps would be cleaning their water, feeding them with healthy food, and in the first place, buying a quality breed of Bettas.


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