New to betta fish. Does he look okay?

Hey. We got a betta fish for our toddlers a few months ago. Obviously we do all the care. This is only our second attempt at having a fish. The first one didn't go well and we are pretty sure it had a gill deformity. But now I am paranoid and figured I would ask some fish people.

Here are some pictures of him in reserve order chronologically because I can't get them to swap on mobile. He started out bright blue and has darkened and gain some purple. His fins are also longer and some small tears he had have closed up.

I think he is doing well. He eats fine and is active and responsive. I read that bettas can grow dark as they reach maturity due to a marbling gene. Not sure if he has that, but it fits.