oh, btw, yah, I have...and its not pleasant. I only saw the danio though - not the cory which had an even more distince hole.
This is what I posted on the other forum when it happened...it gives details about exactly what happened.
"Alright, as some may know, I found a cory that died, apparently from "exploding." There was a hole in its stomach that definitely should not have been there. WELL, after setting up a new ten gallon tank, I sat myself down in front of the 55 to see how the ottos I had just transfered to it were doing. What did I find? A zebra danio, half floating, half swimming. Also, in another thread, there was mention of zebra danios that appeared to be OVERLY, very overly, distended in the stomach, but which showed no signs of extended scales or off-kilter swimming. We had determined it was possibly that they were females that were holding their eggs. However, the one that I found (which had been one of the "fat" ones) has gone too far, I think, to just be holding eggs. It's stomach is grotesquely distorted and I do not think she will make the hour. Her tummy looks like it is bleeding from the inside and it appears the scales are pulling apart plus she is breathing rapidly and is trying to lodge herself in the floating plants at the surface. "
So, thats what happens - for me at least

(this fish died soon thereafter)