What is a Betta fish tumor? 

Betta fish are brilliant with their stunning colors, flowy fins, and beautiful designs. Betta fish can be affected by many illnesses including tumors or lumps. This article will cover the concern “What is a Betta fish tumor?”, its causes, symptoms, treatment, prognosis, etc. 

What is a Betta fish tumor?  

A Betta fish tumor is a lumpy growth or tumor that appears on the skin of Betta fish. Tumors can grow on any part of the fish’s body and they may or may not be visible to the naked eye. Tumors can be external or internal, while the latter is sometimes impossible to see. 

The size of Betta fish tumors ranges from being so small that you can barely see them with the naked eye to being so big that it seems as if your Betta fish is growing another fish on them. In the case of small tumors, you’ll have to notice your Betta’s behavior to determine if there is something wrong with them. 

What are the causes of Betta fish tumor?

Following is the list of factors involved in causing Betta fish tumor: 

  • Genetic deposition
  • Viral infections
  • Low-quality diet 
  • Poor water parameters

Keep in mind, all outgrowths are not tumors or cancer. Instead, some of the Betta fish tumors show a white appearance, which is a sign of an ulcer or benign abscess. However, fungal infections can also cause cotton-like growths on your Betta’s body. 

What are the symptoms of Betta fish tumor?

The symptoms of Betta fish tumors observed around the world are given below: 

  • Physical growth on Betta’s body
  • Inability to swim properly 
  • Anorexia (lack of appetite) 
  • Lethargy 
  • Difficult breathing 
  • Poor health conditions 

Sometimes, it’s difficult to differentiate a Betta fish tumor from another condition with an untrained or unassisted eye. For instance, in the case of swim bladder disease, the body can take up the appearance of abnormal growth as a result of constipation or fluid retention. 

For differentiating Betta fish tumors from conditions like swim bladder disease, you should check for the above-mentioned symptoms and continue your search for the solution. In some cases, there can be multiple tumors growing in different locations or clumped together. 

What is the treatment of cancerous Betta fish tumor?

There’s not any specific treatment for Betta fish tumor but if you live near a veterinarian, you can ask for surgery to remove the tumor. However, surgery isn’t a comfortable situation for your fish and the success rates are also next to none. 

Moreover, a tumor has the ability to regrow itself, which means if your veterinarian has removed the tumor by surgery and your fish recovers, there’s no guarantee that it will be gone for good. Betta fish have a lifespan of around 2 to 5 years, so most Betta owners opt to keep their fish comfortable for the duration of their life. 

What is the treatment of Non-cancerous Betta fish tumor?

It’s nearly impossible to treat cancerous tumors in Betta fish, but if your fish has non-cancerous growth as a result of secondary disease, the following are the steps for its treatment:


The first step to treat non-cancerous growth in Betta fish is separating or isolating the affected fish and moving them to a quarantine tank to prevent spread to other fish. Make sure you mix water from their original tank with quarantine tank water to avoid shocking effects in them. 

Water parameters check 

The ideal water conditions can treat both cancerous and non-cancerous tumors in Betta fish. The ideal water parameters for Betta fish are: 

  • Ammonia (0 ppm)
  • Nitrates (less than 20 ppm) 
  • Nitrites (0 ppm) 
  • pH (6.5 – 7.5) 
  • Temperature (75° – 81°F) 


Medication for treatment of non-cancerous tumors depends on the condition causing them. Antibacterial or velvet disease medicines can be used to treat tumors. However, you’ll not hold your fish and put medicine directly on the growth, but you’ll add it to the tank water. 

If the cause of the tumor is unknown, adding aquarium salt (not table salt) can improve the overall health of your Betta fish. Fungal, bacterial or viral tumors can be treated by using antibacterial medicines and maintaining ideal water conditions. 

Water changes 

Changing water on a regular basis is important for the overall health of all the aquarium fishes. But while treating non-cancerous tumors, it’s recommended to change 25-50% water daily in case of bacterial, viral or fungal infections. 

How to prevent the Betta fish tumor? 

The measures to prevent Betta fish tumor include: 

  • Maintaining a high-quality diet. 
  • Changing 25% of water every week. 
  • Using a filter system. 
  • New fish kept in quarantine. 
  • Purchasing from a reliable breeder. 
  • Check Betta’s lineage before buying. 
  • Proper cleaning of their aquarium tank. 
  • Making sure tank water is disinfected.


Today, we covered the article “What is a Betta fish tumor”, its causes, symptoms, treatment, prognosis, etc. From the above discussion, it’s concluded that Betta fish tumor appears on the skin of the fish due to improper tank cleaning, and infection from a bacteria, virus or fungi. 



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