The shrimp looked healthy no marks I did molt while I was acclimating it the other fish that are in the tank are one fire shrimp two clowns and 2 royal grammas there is also a few snails when I put the peppermint shrimp in it just swam to a rock then disappeared next day it was dead on the bottom before that I put 3 cardinals in over a 3 day span all dead then watchman goby then a blenny and a aptasia eating filefish the file fish I took off the powerhead unfortunately
Anecdotally I could NOT keep inverts other than hermits and emeralds (no cleaner shrimp, no small peppermint shrimp) in my 60 gallon without them "disappearing", and I 100% suspect that my single Royal Gramma was the cause because after I removed it I had no issues with even smaller, more sensitive shrimp (sexy shrimp). It was a giant asshole, it would charge and gape at two full grown PJ cardinals, a firefish, sleeper goby and basically anything in the tank that wasn't a damsel, which are the real world class assholes.
If it were me and the rockwork made it possible, based on what I've seen them do I would try sticking the grammas in a time-out* (two breeder boxes, one fish each) and try re-adding a basic invert or fish. If it survives, you've got your killers. Since the gramma's were introduced first it's possible they've staked out their territory and god help anything that stumbles into it.
* Edit - If I was running a sump I'd toss them in there (separated). Supposedly you can "reset" their territorial instinct by keeping them in a new environment for a bit, let the other fish get established and draw new borders, then bring the grammas back. Granted I've only had one gramma, but it's the only "X" factor that I could single out.
