http://www.angelsplus.com/ArticleDecap.htm
is well worth a look.
I feed my fry decap at 4pm being there last feed of the day.
I pre-soak for 2 min as it will swell 35%..best in the spoon rather than in them.
they will graze on the decap on the bottom of the tank all night until there is none in the morning.
they do look like a small flock of sheep grazing on the bottom.
D