UPDATE: Just did a water change, and to confirm my above suspicion, up through the vacuum tube on his side, I saw two giant poops, so I guess he went! =) So yup, he's better now!! :D
I have a male that has the largest rounded belly- most would say he is bloated.. but he eats, poops and acts just fine. Just a rather large stomach. He is older, his back is curved down quite a bit which makes it look rounder as well.
Glad he went to the bathroom and is doing good, sorry I couldn't help when you and Flowers asked :( Just bad timing.