Betta Fish: Bali is getting a little chonky

I’ve had Bali for quite some time now. I got him with severe fin rot, frail, and pale. He’s been thriving since giving him a proper home, but now he’s oddly fat. I fasted for 3 days, and just gave him a quick ten minute epsom salt bath today. Haven’t tested water parameters yet, just did my weekly water change today (20-30% depending on how I’m feeling). These pictures were right after my water change, with the lights off so I promise my water isn’t *that* dirty. Little brown diatom algae issue per usual. Nothing else has really been abnormal, but do you think this can get better? Any other input would be appreciated.