Well, if it was a tumour, there is not a lot you can do. Nothing that doesn't require vast sums of money.
The fry story is a bonus. The legacy lives on!
I've seen similar looking protrusions in my glass catfish, they live happy for a while, then they look less pleased, at that stage I normally do what you did.
I'm almost 100% convinced it was a tumour in both cases.
You made the correct choice I think, so have a beer!
(It's bad, but good)