He looks like he's swimming oddly and he's breathing fast.
I'm not sure about bloated, but he does look pretty full.
You said he was separated right now? I wouldn't treat him until I was sure there was something wrong, but he does look a little off.
Has he been at the surface a lot? I once had a guppy who was acting like this and then the next day he was completely fine. I have absolutely no idea what it was.
Sorry if I'm not being much of a help!
4 Male Bettas: CT, VT, VT, PK
3 African Dwarf Frogs
Many Ghost shrimp
Zebra Nerite Snail