is my betta suffering from fin rot?

[coppertown]

I've got a super delta betta in a heated 4-gallon planted tank with a low-flow filter that's working great. Water parameters are all good - pH is 7.0-7.2, which I know is on the higher side, but I've heard stability is key, so I'm not too worried about it. Ammonia and nitrites are 0 ppm, and nitrates are 5-10 ppm.

I've noticed he's a bit of a fin nipper, so I've caught him at it a few times and rearranged the driftwood and rocks in the tank, which seemed to help for a bit. But now, I've started to notice his fins curling, and I'm not sure what's going on - is it new growth or fin rot? There's no sign of brown or black edges on his fins, and I haven't seen any rips or tears going further back towards his body.

I've added a few photos - the first one's from when I first got him, and the other two are from recently.

[coralwave]

His fins look perfectly healthy to me.

[kalinda]

That's one stunning betta, I must say.

[oceanrider]

I completely agree with everyone, his fins look healthy and he's absolutely stunning.