Betta With A Huge Growth? Cancer?

[candycorn]

So my beloved office betta has a terrible growth as you can see. (he is white in the photos...my work camera had a flash I could not turn off so I blocked it with my finger and now he is pink!)
He is in a 3 gallon planted tank with filter and heater. He has been with me for over a year. The growth started as some strange bump about 3 months ago...but has definatly progressed. I fear it is cancer. His fins have also become very straggly in the last week or two. I have added traces of salt on the advice of my wife who has been a fishkeeper for years.
Has anyone seen this before? Is there any chance it could be something else? I breed show mice, so I understand how to ease the pain of a mouse with a large tumor and at what point they are in pain...but I am at a loss with a fish. How do I know when he is in pain/too far gone? I realise that fish are not mammels and don't express pain, but I don't want him to suffer either. This is my first fish with this sort of growth.
Any thoughts?

 

[Flute]

Poor guy, doesn't look very nice for him
I think you'd probably get more replies if this were in the emergency section. Might be worth a mod moving it over?

 

[reidcaskey]

Very interesting! Thanks for sharing!

 

[GaryE]

It is probably an incurable tb lesion. In case, do not touch the water without hand protection, if you have open cuts or are immune compromised. Transmission to humans as a skin infection is rare, but possible. There is, sadly, no hope for the fish, and I would euthanize the poor guy.