Why do they keep dying?

I started with Cherry shrimp about 2 weeks after starting the tank. They all died in a week. I chalked that up to the tank not being fully cycled. Then I added 4 ghost shrimp a couple weeks later and all died in a few weeks. The clown pleco, nerite snails, and longfin Danio are all doing really well. Another round of 6 ghost shrimp and all except one died in the first few weeks. One had a horsehair worm but I guaranteed for a few weeks and it expelled the worm a few days into the quarantine. My water parameters appear to be ok. Maybe just a bunch of low quality shrimp from petco?