I just bought 30 ghost shrimp for my 30g tank today. It only had snails in it before hand. When I bought them, I had 3 maybe 4 berried shrimp. 2 of my berried females died before they could release. I bought them from Petsmart this morning. I've lost 11 out of the 30 so far. Is that a normal to lose about 1/3 of them? I got them because they were cheap and hoping to let them breed and then feed them to my 4 GSP.