You've got some great-looking fish there.
I'm trying to get a community tank set up but I have to tear it down to replace the substrate. All it had in there were four panda cory cats and two guppies anyway.
Popo has handsome, gorgeous fins. I love the way they flow behind him. And he's got such a cute little face, he's adorable. But you're right, he does look a bit bloated. :( Along with the pea, you can use epsom salt. It's 1 tsp per gallon, so maybe use 3 tsps if you think the drawer is 3 gallons? If the drawer isn't quite 3 gallons that's fine, the dosage can go as high as 3 tsps for super serious cases. Which hopefully Popo will not become one.
Haha, I love his current setup with the cosmetic mirror and the lava lamp. He does look like he enjoys his lights.