Australian Rainbow abnormal growth

One of my Australian Rainbows has slowly developed a growth in the lower part of its mouth. Lately it is so bad that he can't close his mouth at all. I'm worried that if it continues he will just be suffering and eventually die. Has anyone heard of this before?

I took a video to try and show what it looks like. Please, any input would be great.

 

Hi,
I'm not very good with disease, so hopefully someone can help you today.

 

Sorry to hear about the sick fishie!
Though I've never seen one before, it could be a fish tumor.
https://www.petmd.com/fish/conditions/cancer/c_fi_Cancer_and_Tumors#.T_p8jZGdv3U Here is a link with some info on them. Hopefully someone else can provide better advice. Good luck!

 

Someone left a comment on the youtube video saying they thought it was Mycobacterium Mariunum or Fish TB. Does that sound likely? I did some reading on it and its kinda freaking me out.

 

TB is frequently thrown out as a diagnosis, but it's actually VERY rare in aquaria. In fact, one member (iZaO Jnr) had a fish that was very thin and some members thought it might be TB. He ended up ruling that out, and I believe his fish is fine now. You can read about his adventure here: