the eggs can also fall in between coarse gravel and the glass; when my danios were dropping eggs all the time, the eggs were easily found by looking at the edge of the gravel. A couple days later, they're those splinter-sized fry, most of which then get eaten the minute they start scooting around. I kept some alive by siphoning the eggs out and depositing them in another tank.
mine might still be dropping eggs, but with a bunch of bottom feeders in the same tank now, I doubt I'll see any more of them.
edit: some danios may look fat because they are fat; they are voracious eaters. if the fish has kind of an elongated/squarish underside, she may have eggs stored up.
All cwt posts are implicitly appended with "just my two cents".