burgerm- the planted rye will only supply forage food for the grass shrimp for a short time; weeks to a month. As ML says g.shrimp need some form of weed cover and forage (decaying organic matter/weeds) year round.
Maybe ML will post the names of the pond weeds that are in his pond.
Grass shrimp do best in ponds where there is fine leafed pond weeds; types like sago pondweed, milfoils, narrow leaf pond weed, elodea, Najas (slender naiads, bushy pondweed).
You could probably collect some for stocking in your local weedy ditches, marshes or ponds.
