Bloated fish

[Rikko]

Swim bladder infection? I've had so-so results treating with Melafix, though really for internal stuff a medicated food will work better. Tetra used to make a medicated food that's been banned and regulated all to hell, but I believe I've seen recipes for mixing flake food with erythromycin (sp) tablets to conjure up an identical treatment.

Eggs? Usually they don't come up that quickly..

Intestinal blockage? (Oh, crap)

Dropsy? Usually it comes on gradually and is accompanied by scales popping off.. Unlikely from what you've described.

What's your water quality like? If you did mega water changes you might find it clears up on its own. If you're worried and a swim bladder infection looks about right, you could have a go at some kind of antibacterial treatment.