The Cleaner Shrimp is gone...

I fed my tank a 1/4 cube of Mysid shrimp and was watching all the inhabitants "get excited", then I noticed I didn't see my Indo-Pacific White-Striped Cleaner Shrimp (Lysmata amboinensis). He was under the overhang of a rock low to the sand (which would be uncommon) and he didn't look right. He was moving but his shell seemed odd, and he seemed to be reacting to the food but wasn't going after it.

I left and returned about 30 minutes later and found two Narsarious Snails (Family: Nassariidae), a hermit crab, and a Bumble-bee Snail (Family: Pusiostoma) all over the remains of the cleaner shrimp.

Within an hour or so all that remained was an empty husk.

Was the shrimp mid-molting and was vulnerable? Or could it be a change in salinity (I had let my fresh make-up-water lapse a bit and added quite a lot at the same time)?





Here's a picture of a hitch hiker Brittle/Serpent Star, perhaps 1" wide.