Free Swimming Danio Fry Question

[Shigshwa]

I was wondering, other than the fact that free swimming fry swim (obviously), should Zebra Danio fry have little pouches under them when they're free swimming? I notice that both of these fry swim in a darting motion occasionally, but then stick to the wall sometimes.

 

[toddnbecka]

I've never seen danio fry stick to the glass after they've become free-swimming, what else is in the tank? Possible stray eggs on some new plants?