Emerald crabs dying???

[Bruen]

Have a 20 gallon tank which has five fish, hermit crabs, snails and coral. I also have two emerald crabs which I have had for a couple of months. Yesterday both crabs where fine. Today I have come home from work and they are both either dead or molted. Everything else in the tank is fine. One emerald crab is lying upside on the front hanging of a rock and the other is lying upside down on the sand at the back of the tank. Can you please advise if they are molted, molting or dead. How long do they take to molt? Cleaner shrimp are all other them, can they cause them to die when molting??

 

[Bruen]

One of the emerald crabs breast plates are open and the cleaning shrimps are fighting to get into it. Please see pics, would this be a molt or is it trying to molt and being eaten in the process.

 

[ivan_dalmatia]

He might have just moulted, pic is unclear? The cleaners may be eating the shell ( exoskeleton of your crab to get calcium, witch is why I always say don't throw out your shedding of a invert=extra calcium if they need it (by consuming it)