Tumors in Pet Fish

Tumors in pet fish are abnormal growths of cells that form masses or lumps within the body. Tumors can develop in various parts of a fish's body, including the skin, internal organs, and muscle tissue. These growths can be benign or malignant, and their effects on the fish's health can vary depending on the type, size, and location of the tumor.

Tumors in pet fish are relatively common and can occur in both freshwater and saltwater fish. Tumors in fish can be caused by a variety of factors including genetic predisposition, exposure to environmental toxins, and infections. In some cases, the cause of the tumor may not be known.

Symptoms of Tumors in Fish

  • Fish with tumors may have difficulty swimming, and exhibit abnormal behavior.
  • Have visible growths on their body.
  • In some cases, tumors may go unnoticed until they grow to a large size.


  • Genetic predisposition, just like humans, some fish species may have a genetic predisposition to develop tumors.
  • older fish are more prone to developing tumors.
  • Environmental factors, poor water quality, exposure to chemicals, and other environmental factors can increase the risk of tumor development.
  • Viral infections and some fish viruses can cause tumors in fish.

Can tumors in fish be treated?

There is currently no cure for tumors in fish, however, some treatments may help slow the growth of tumors or reduce their sizes, such as surgery or radiation therapy.

How are tumors in fish treated?

Fish tumors can be difficult to treat and in some cases, they may not be treatable at all. There are a few approaches that can be taken.

  • Surgery- if the tumor is in an accessible location, such as on the skin or in a visible area of the fish, it may be possible to surgically remove it. This is typically done by a veterinarian or an experienced fishkeeper.
  • Chemotherapy- in some cases, chemotherapy drugs may be used to treat fish tumors. However, these drugs can be toxic and can have significant side effects, so they should only be used under the guidance of a veterinarian.
  • Even if the tumor cannot be treated directly, supportive care can help to improve the fish's quality of life. This may include providing a clean and healthy environment, ensuring proper nutrition, and monitoring the fish for signs of distress or pain.

Are tumors in fish contagious to humans?

There is no evidence that tumors in fish are contagious to humans or not, fish tumors are typically caused by genetic mutations or environmental factors, such as exposure to carcinogens (that can cause cancer) or poor water quality.

These factors do not pose a risk to human health, and there is no evidence that fish tumors can be transmitted to humans through contact with the fish or their environment.

It is always important to take basic hygiene precautions when handling fish or their environments, such as washing your hands thoroughly with soap and water after handling fish or aquarium equipment. This can help to prevent the spread of any potential pathogens or contaminants that may be present.