Betta Fish: Odd dent in her tail?

Sorry for the music, lol.

She has a small dent in her tail and i’m not entirely sure why. It definitely dosnt look ripped and she’s in lovely condition otherwise, no lethargic swimming and VERY exited to eat. she only glass surfs when i’m at the tank, so i’m not sure why this dent is there, is it something i should worry about? I’ll send a more specific photo in the comments.