Is my Barb ok??

I bought 3 tiger barbs about 3ish years ago. They were the same size at purchase. One began growing fatter than the others, I figured it was just getting the food first so was chunkier. Buuuut I had a housing crisis during the onset of Carona and had to store my tank at someone's house. I got it back a few months ago and the barb was HUGE. And looks to be getting fatter somehow?!? I'm worried now bc it looks like it's gunna literally pop...?

Water was tested and is good. It swims fine and doesn't show signs of worms or disease.

It's hard to say from the photos. What are the numbers for your water quality test results? What is the maintenance routine and did this slip during your housing crisis at all?