I've fed extra cherry shrimp from my planted tank to my fish before...they seem to be worth more as LFS trade ins though... Ghost shrimp ime are just as easy to breed. But yes I've fed them w/ no issues. as for eating eggs ect. unless you're tossing more then your fish can eat into the tank and they are maintaining a population the chances of them eating eggs and fry is minimal imo. they stay tiny, and prefer algae as a general rule. I wouldn't put anything past anything.. but I've never heard about them predating fry or eggs.