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Tumors And Cancers in Fish

Tumors And Cancers 


Fishes develop tumors and cancers, much like humans and other animals. However, sharks are a type of fish which never develops cancers.


Symptoms and Types 


Most tumors are seen as bumps or lumps under the fish's skin. But the location and signs of the tumor can be different for each fish, and depend greatly on the type of tumor. Unfortunately, internal tumors or cancers display symptoms once it has become to late to save the fish. Also, the fish’s ability to eat and swim will be affected, causing a rapid decline in its health.


Koi fishes usually get tumors in the reproductive organs. They will have swollen abdomens and the illness can become terminal. Conversely, goldfish are susceptible to fibroma tumors and sarcoma cancers. While Gypsy-swordtail fishes, generally develop skin cancer (malignant melanoma).


Another type of tumor is found in the gills. It causes the fish to be unable to close its gills, and is due to a thyroid dysfunction. Despite its seriousness, the tumor has a good success rate when it is treated.




Most fishes get tumors or cancers due to genetic predisposition. Some fishes, however, can get tumors or cancers from a viral infection.


Comments  4

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  • Sharks and cancer
    06/02/2012 01:30pm

    It's not true that sharks don't get cancer. That was a story made up by some guy so he could sell make money by selling shark cartilage as a cancer cure. :(

  • 05/17/2014 01:41pm

    No doubt a Japanese guy. They seem to hold many insane beliefs with no scientific proof. And they're not concerned in the least that those irrational beliefs are leading to the extinction of many animals; whales, rhinos, and sharks, just to name a few.

  • Tumors in fish.
    04/07/2016 01:59am

    Sadly I was looking this up because my dinosaur bichir I've had for 5 years developed a tumor and I knew I was too late. He couldn't even swim to the surface to get food, and sadly I didn't want him to go on like this... I had to put him out of his misery. Call me a bad owner but I loved that fish so much I couldn't stand to watch the horror. My cichlids even brought food to him

  • .
    04/07/2016 02:01am

    Every living creature has feelings. Those cichlids were actually friends. Seems weird but they did care.