Can a Goldfish Have a Tumor?

Can a Goldfish Have a Tumor?

If your goldfish has a lump or it stops eating, it can be a sign of a tumor. Here are the main causes, signs, symptoms, types, and treatment for tumors in a goldfish.

Can a Goldfish Have a Tumor? Yes, Goldfish have tumors like all other fish. Whenever you notice a bump on your fish’s body, do not need to panic. Some tumors are not dangerous for their health, but some are life-threatening. Tumors in fish are mostly caused by genetic mutations, toxicity in water, and untreated infections. You can treat tumors in a goldfish by medicines and surgery.

Can a Goldfish Have a Tumor?

Sometimes people get shocked or surprised to know about fish cancer. It is also helpful for those people who keep fish and who love them. In this article, 

you will find a complete guide about tumors, and whether it is a tumor or not. Some bumps seem they are tumors, but they are just due to infections. You have to make sense of both of them because it is essential for your goldfish healthy life. 

Types of Tumors in Goldfish

There are different types of tumors are generate in goldfish. Here will discuss a few of them. 

Nerve sheath tumor

Thus, cancer is initiate in different fish species, but goldfish are more common. They begin from neural crest cells but appear in subcutaneous nerves. The diagnostic fish looks normal inside and outside.

It develops steadily and might cause loss of function, pain, and harm to the nerves and spinal cord. The nerve sheath is a myelin layer, and they are the connective tissue that shields nerve fiber. Nerve sheath raises under the cells covering.

Fish having tumors may texture a burning sensation, weakness, pain, numbness, and a mass. Their actual reason is anonymous. It can cause by genetics or schwannomatosis. This tumor breeds within the nerve and affects them. It includes neurofibromas, schwannomas, and others.  


It is also known as pigment cell tumors are derived from chromatophores usually found in the goldfish skin or other fish species and reptiles or amphibians. There are four classifications of chromatophores, and they contain different pigment types.

The melanophores encompass brown or black color. Xanthophores comprise yellow tint, iridophores hold colorless pigments, and erythrophores encompass red pigment. All four types originate from the neural crest.

It is a very uncommon tumor that presents in fish. Most outdoor fish suffer from this cancer than pet fish. Their eyeballs get these types of tumors, but it can occur around face sides or dorsal fins. It is difficult or unable to treat. It caused eyeball removal in a severe condition. 

Gonadal sarcomas

This cancer originates from gonadal tissues but is unable to demonstrate with a 100% guarantee. Because ovaries are extremely duplicating tissue, their tissues are mostly not found.

It is more often found in female goldfish about 8 to 12 years of age. It is too late to know about it. Fish grow very extensively during the reproducing process. It is very problematic to say egg from cancer. 

White tumor

Occasionally, you may notice that your goldfish have a white lump. It may be not cancer, an abscess, or an ulcer. It will fill out with pus and might burst over time. If your goldfish bump bursts, make sure to separate the fish from the aquarium when he lives with other fish.

When fish lump bursts, it become a great sore, and your fish needs extra care. You should frequently change aquarium water and should check the tank’s condition.

If an abscess goes too severe, your goldfish will die. It can also be an ulcer and makes the skin red from the edges and seems sore. 

Location of tumors in goldfish

Cancer can found all over the goldfish body. The location of the lump is not similar for all fish people reports tumor in a few places. Fish can receive cancer in gills, eyes, head, skin, internal organs, and find. 

Cancer in gills

Sometimes, you may notice a tumor on the gill, which may be hyperplasia. It mostly develops when fish gills are damaged due to bacterial infections, physical injury, or parasitical and cause by toxins.

After treatment, it develops gill tissue over the affected area. This new crust creates bumps that seem like cancer. With passing time, it will enlarge or greater, with skin growing.

If the hyperplasia in serious condition, your goldfish can develop cancer. It is minor, and it is treatable and, your fish go back to their consistent situation. 

Tumor located on the head

It is another most common place where people found the lumps. In some cases, it is cancer or, in others, it may not be a tumor. Sometimes bumps occur on the head due to bacterial infections, called columnaris.

It is an infection that can harm all fish in an aquarium. Columnaris is also known as guppy disease, wool disease, saddleback disease, and cottonmouth disease.

You have to make sure your goldfish have a tumor or columnaris because it is a life or death question for your fish. In some cases, after treatment, you may found it is a tumor, not a columnar. 

Tumor found in the stomach

It is another common place where your fish can occur tumors. If there is a bump or swelling on a fish’s belly, it can be cancer. In some cases, it is not always a tumor.

It can be a swim bladder disease, constipation, or bacterial infection. In that situation, the fish does not eat the right amount of food, unable to poop, lethargy, and bloating are the symptoms of constipation in fish and not a tumor. 

The tumor occurs on the goldfish’s side

In some cases, you may find swelling on the fish side, here it is also a tumor or not. When you notice a bump on the fish side, it may be due to some other causes such as swim bladder disease and dropsy.

Swelling on the fish side may be due to swim bladder disease. In this disease, fish is lethargic, unable to stay buoyant, do not eat proper food. In dropsy, your goldfish suffers from a curved spine, bloating, and pinecone scales.

Goldfish can live long with cancer, but when they have severe dropsy can die within a couple of days. If other fish in the aquarium is also getting sick, ill, or have bumps, it roots by bacterial infections. You should treat the tank’s water with anti-bacteria medications. 

Symptoms of tumors in Goldfish

The most vital sign of tumors is their lump size. The lump size can alter after sometimes it is large or it is small. It is too hard to detect internal cancers, and their behavior will change. 

Their earing time may enlarge, or they stop eating, they find trouble when swimming. All indications may occur when they have another illness, not only because of cancers. They do not look active and sharp and it the main sign of a tumor in a goldfish.


There are multiple causes of goldfish cancer. Tumors may trigger by purely genetic defects, biochemical infections or viruses, contact with toxic chemicals, and fish buoyancy issue, providing them fault food, unclean or dirty water. 

How to treat tumors in goldfish?

Most cancer or tumors’ treatment are incapable Because they can not diagnose because they are internal. These types of bumps can detect at very early stages. Some tumors are treatable such as gills.

Some tumors such as nerve sheath tumor and pigment cell tumor can remove surgically by cryotherapy, MRI, or excision. Some types of tumors can treat by applying liquid nitrogen, pain management, or antibiotic therapy. 

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