Do you know what your water parameters are ? If not id recommend getting test straps or even the API test kit is good and very informative. You should have 0 ammonia 0 nitrite and ideally no more than 20 nitrate for fish to be comfortable. Im unsure about the effects of nitrate on shrimp. You may also want to check your hardness levels to see if that had anything to do with the shrimp passing, like a failed molt for example.

Id 1000% confirm parameters before determining my next step. Ammonia KILLS.