Fin rot? Or funky tail

[Courtney S.]

Hello, this is Billie. He's my first betta and I'm new to being a more informed fish parent. His fins have looked like this since I got him a week ago. Is this normal? Fin rot? Stress? He's now in a planted tank with a sponge filter and in-range water parameters, so I don't think it's an issue from my water. Maybe bad water previously? Thoughts and advice appreciated!

P.s. is he a half-moon?

[Colu]

Am not seeing any Redding to the edges of the fins that would indicate fin rot it could have been a previous infection and the fins haven't fully grown back what I would do is add some Indian almond leaves as they have antibacterial and antifungal properties are really beneficial to Bettas and monitor I think it just need some time to grow back fully @Courtney S.