I got 200 from a previous order and can say I only had one mort as well... I put 50 into a pond with only lake chubsuckers in it and 150 into a pond with just shiners, suckers and minnows in it. So there were absolutely nothing in there that could eat shrimp. I will seine it this fall to see if there was any reproduction. Almost any place that has trophy sized RES has a population of grass shrimp. They are a top notch food for RES as well as just about any other fish. And they make a top notch bait as well...
