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I have a tilapia, and recently it has developed a growth about 3/4 in. in diameter, and about 2mm tall on its neck. The fish itself is about 8 in. long, and is probably 9 months old.
I've looked all over the internet, but could not find anything like it.

Any help is greatly appreciated!

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Do you have a photograph? That might help us help you. – Ash Mar 24 '14 at 22:44
No I don't. But I will try to describe it better. – Azzie Rogers Mar 24 '14 at 22:53
Growth as in hard tumor-like growth? Or some kind of fungus? – Spidercat Mar 24 '14 at 23:27
up vote 3 down vote accepted

Fish, just like us, are subject to various forms of cancer and this sounds like an internal tumor manifesting externally on your fish. If it is a thyroid cancer, there is a possibility you can treat this with iodine in the water, otherwise it's inoperable. However, ideally you're able to consult with a vet to:

  1. Confirm it is a cancer.
  2. Confirm treatment possibilities, if any.

Now, I could be very wrong about this and I am not a vet, so this is not a diagnosis in any way. You can use Google image search for "fish tumor" and see some images of growths and compare that to your fish to give you some idea. However, as I noted, the best option is a vet that knows fish illnesses, but that can be a challenge it is true.

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Thanks! I'm pretty sure that's it! – Azzie Rogers Mar 25 '14 at 2:24
@Jaxon - I'd prefer to be wrong about this, to be honest. Your description wasn't detailed, but it was the first thing I considered and it's not really that rare. :/ – John Cavan Mar 25 '14 at 2:53
Not sure why your are assuming it is "inoperable", I know my exotics vet does tumor surgery on fish. – James Jenkins Mar 25 '14 at 10:28
@JamesJenkins - Do you know that it successfully treated the cancer or just cosmetically removed the growth? What I've read is that it's you can't cure it through surgery. – John Cavan Mar 25 '14 at 10:32
Just like people it depends on the type and if it has spread. – James Jenkins Mar 25 '14 at 10:38

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