Not sure if it's been mentioned, but, if there are any fish in there that can fit them in their mouth, it may have became a meal for one of them. I had a yellow watchman goby, and I added about 5 or 6 sexy's with the flow off (so they could settle in nicely) , and how foolish that was... flow off + yellow watchman waiting to be fed + adding in 5 sexy shrimp that can fit in his mouth = Buffet!
And as been mentioned, they are sensitive to water chemistry and salinity changes, so if not properly acclimated it could have been that as well... or again, it could be a simple molt and it's hiding on you.
Making me want to go get some sexy's for my tank... cute, interesting little buggers they are!
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20g BB Mixed Reef // Coralife 150w HQI // AquaC Nano // Koralia 1 & Seio 820 // Jager 200w // AC50
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