Bump on goldfish

[Divinityinlove]

On the fish's right, but on the viewers left is a bump. I just noticed today.

Have you experienced this before?
The only change is I started feeding some new pellets. The other two are fine.

 

[Kyanite14]

I’ve heard of some goldfish developing tumors, could also be a damaged spot from scraping against something. Hard to tell from one angle. Most tumors are benign but I would keep an eye on it. Keeping the water clean is the best thing to do right now, but if it grows and starts to affect its ability to swim it’s more of an issue. It’s kinda hard to find a vet that knows how to surgically remove tumors on fish in my area…