A little help for a new here

[Freezers]

Hello folks I am new to the forum but I have piranhas many years now I have 2 rbp on 200+ litres with 2 internal filters one of them it's bio so the water is pretty good... Before a few days I notice something on the mouth area any idea?
It behavior normally and eats.
Maybe a hit from the mate or a hit to the walls.?

 

[Freezers]

Photo here

 

[Deadeye]

Welcome to the forum!
Hard to tell exactly from the picture. It sounds right that there was some sort of injury and it’s in the healing process.
kno4te
What is your water change rate? Typically the best way to help with this is increased water changes to keep the water nice and clean (or cleaner) so it heals best. Piranhas heal fast.
FWIW, piranhas in groups of 2 tend to bicker a lot, so there is likely a lot of fighting which can result in injury. They are safest alone or in large groups to avoid constant beating on each other.

 

[kno4te]

Seen those before on fish rubbing on glass. It’s happening more than once. Can leave alone and try placing some plants/decor by the glass to avoid any trauma or contact.

 

[Somesed]

Chinple! Not harmful as long as it heals, but unpleasant looking. The general bump may never really go away.