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Home > Fish > How to Handle Goldfish Tumors & Growths? What You Need to Know!

How to Handle Goldfish Tumors & Growths? What You Need to Know!

Aquarium with goldfish

There are a variety of tumors and growths that goldfish can develop, especially as they age. It can be scary to see unusual growths appear on your goldfish, especially if you aren’t sure what they mean and how to care for them. It’s important to know what causes tumors and growths to appear on goldfish, though. By understanding what can lead to these appearing, you’ll be much closer to being able to provide excellent care to your goldfish and, hopefully, treat their condition.divider-fish

What Causes Tumors and Growths on Goldfish?

Growths on goldfish are more common than you are likely aware. Most of the time, growths on your goldfish are benign cutaneous tumors, primarily neurofibromas or schwannomas. Although these growths may be unsightly, these growths are not life-threatening to your goldfish. There are very few medical concerns associated with these growths, truthfully, and little can be done for them. They tend to be present through multiple layers of the skin, which can make complete surgical removal quite difficult.

These types of growths are most common in comet goldfish, but they do occur in fancy breeds as well. It is possible for some growths to become so large that they press on internal organs or inhibit movement for swimming, breathing, and eating, in which case veterinary intervention may be necessary.

It is possible for goldfish to develop cancerous tumors, but these are highly uncommon. Little is known about cancerous tumors in goldfish, so a vet visit is a good idea so they can perform diagnostics and provide treatment guidance.

oranda goldfish
Image By: Rethinktwice, Pixabay

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The 4 Ways to Care for Tumors and Growths on Goldfish

1. Identify the Growth

It can be extremely difficult to properly identify growths on goldfish, but you should first rule out conditions that may look unusual but that aren’t actual growths. This would include fungal and bacterial infections that cause loss of scales or fins, which can lead to a lumpy appearance. Some parasites, like Anchor worms, can also give the appearance of lumps and bumps.

You should also rule out dropsy, which is a symptom of free fluid in the abdomen, which indicates severe organ failure. Dropsy leads to a distinct swelling pattern that causes scales to point outward, giving the fish a pinecone appearance.

If you’ve ruled out other causes of the unusual appearance of your fish, then you’ll need to talk to a vet.

two goldfish swimming
Image By: Hans Braxmeier, Pixabay

2. Talk to a Fish Vet

Finding a veterinarian who sees fish can be difficult, but the American Association of Fish Veterinarians has a search function to help you find fish vets near you. In some areas, agricultural or teaching vets may be the next best thing to finding a vet who specializes in fish.

When setting up the appointment, offer to provide high-quality photos of the growths on your fish. This may help them get an idea of what’s going on and be prepared with a treatment plan when your fish gets to the office.

3. Maintain High Water Quality

Whether you get your fish to a vet or not, ensuring your tank has excellent quality should be high on your priority list. Check your parameters and ensure they are in line with healthy goldfish parameters. Provide your goldfish with regular water changes, ensuring you are properly treating the water with dechlorinator before adding it to the tank. Good water quality is one of the best options for preventing and treating medical problems in goldfish.

Koi and Goldfish
Image By: Aleron Val, Shutterstock

4. Provide a Healthy Diet

A high-quality diet that meets all your goldfish’s nutritional needs is essential to helping them heal from a growth or tumor. Goldfish are omnivores that require variety in their diet, so aim to provide a variety of high-quality pellets, along with nutrient-dense foods like fruits, vegetables, and frozen foods like bloodworms.



Helping your goldfish heal from tumors may not be possible, but most tumors and growths on goldfish aren’t of any serious concern. It’s always a good idea to investigate the environment when growths develop, though, ruling out water quality issues, bullying, injuries from tank décor, and illnesses. Provide your goldfish with great water quality and a nutrient-dense, varied diet to support their overall health. Discuss your options with a fish vet, or an agricultural or teaching vet when a fish vet is not available. They will be able to give you guidance on what exactly is wrong with your fish, as well as being able to provide treatment options to you. The world of goldfish medical care is rapidly growing, so new options are frequently available.

Featured Image Credit: Pexels, Pixabay

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