No it looks to me like they have been munched, blown fins is mainly splits and freys in the tail....I say munched but it would be hard for him to get too, any chance they got caught in the filter intake or somthing?
Trouble is we dont know how they could have been munched or chomped etc....
He's in the side of the tank which DOES NOT have the filter. There's not really anything that he could have caught them on. We took out the coconut shell just in case it was that but its been fine up till now.
Some bettas actually bite their own tails. I have one I keep a ping pong ball in to keep him occupied when he gets aggressive. I tried putting a female next to him but he still did it. I found out for sure he was doing this while I was changing his bowl and he was in a cup he started doing it right in front of me
I've had finrot on Odin that looks like that, bits were just falling away overnight, like fraying, at the time other fish in his tank were getting it too which is why I knew it was finrot, I'd get some myxazin if I were you!