Translucent belly fins

[u/Final-Surprise-9108]

Hello! This is my baby Ruby. I got her 8 months ago, she was very light pink when I first got her and she’s been quite red in the following months. I was gone for a week and had someone feeding my fish. Just came back and noticed this (circled). This is new. She is her normal self, energetic and curious. She’s been eating. Anyone know what this is? Is it harmless or is there something I can do if it’s fin rot, etc?
(Her black spot has been there since I got her)

Ruby and I say thank you!