How do you know if your fish has got cancer?

There is no definitive way to know for sure if your fish has cancer without first consulting a veterinarian, but there are some signs and symptoms that may indicate a potential problem. These include any changes in your fish's behavior or appearance, such as:

- Changes in the structure, size, or color of the fish's body or scales

- Sudden changes in swimming behavior (such as lethargy or difficulty swimming)

- Unusual growths, lumps or lesions on the fish's body

- Abnormal eye appearances, such as cloudiness, bulging or discoloration

- Weight loss despite adequate feeding

- Loss of appetite

- Poor water quality can also contribute to fish health problems