my gf found either a dead emerald on the bottom of the tank,
or one has molted. she sent me a photo but I can't tell from the
photo. it looks just like the crab would, but it's on it's back.
This species must molt in order to grow. Generally at night, it will lay on its back and exit its exoskeleton. A new exoskeleton is excreted and will harden over a period of several hours. The animal is vulnerable at this time and should not be disturbed. Proper iodine levels assist with successful molting.
yup, they molt for a fact. Because I was thinking the same think "ah, **** two of my emerald just died"... Few days later, I see why do I see still three emerald crab??? They when I realize it must have been their molts.
Danger, Danger.. Your emerald is getting bigger, so they could destory bigger things..