Betta has white ball type thing on fin?

[abrage22]

The betta I've owned for a couple years now seems to have developed this weird, white, I think? fuzzy ball hanging on its fin. I'll attach a picture. He's in a divided 20 long with one other betta, who doesn't have one of these on his fins (although they're obviously separated). 80 degrees, all normal parameters, I just want some opinions on what this is.
Thank you!

 

[trickshot3102]

Could be fungus

 

[abrage22]

His little ball of whiteness has turned into a much larger fuzzy ball. He still seems perfectly happy/fine otherwise...
Could I possibly physically remove the growth myself, like scrape it off with my finger? Or is that way too out there in terms of dangerous...?


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