Shrimp Dying?

[Timbits]

Hmm if you have a brittle star and its alive and healthy for quite some time then that will rule out any copper being in your tank cuz it's an invert also. Also if there is copper in your tank pretty sure the shrimp won't last 3-4 months either. Maybe they got killed somehow, I had a cleaner shrimp in my tank that does awesome but I can't keep peppermint shrimp alive. Had tried a bunch of times.