What could do this to my Emerald Crab?

[daveverdo]

I just checked out my tank and saw that one of my Emerald crabs appears to be mutilated. He is missing a large claw, several legs and a chunk of shell (see picture).
What could do this?
The only things I have in my tank (that I know of):
2 Emerald Crabs
4 Scarlet Hermits
Cerith Snails
Trochus Snails
Astrea Snails
2 false percs
I was going to take him out and euthanaze him but haven't yet. Do you think it will come back from this?
Dave

 

[alyssia]

Are your sure it's not a molt?

 

[daveverdo]

Are your sure it's not a molt?
Yes, that is what I thought at first until he hobbled away on the 5 legs he had left.
He is missing about 4 legs, 2 claws, and about 1/4 of his body.
I laid him to rest, thinking he wouldn't make it too much longer.
He was larger than the other Emerald but I don't know if that means anything.
I am thinking maybe Mantis lurking in the rocks.
Dave

 

[renogaw]

or a rock could have landed on it, did you have an avalanche you know of? too bad you put it to sleep, one of my crabs looked like it had meat coming out of its main shell only to molt the next day. doubt it would have grown back the claw though.

 

[cnall]

Hey dave I was just wondering if you ever find the culprit. Sorry to hear about the emerald

 

[stanlalee]

a mantis would have probably finished him off. my guess is a rock or something toppled him. But who knows if its a mantis you'll know soon enough since you have your share of inverts and small fish.

 

[swlover]

Humm, I've seen my clowns fight with my emeralds..even pick them up and sling them around. Especially during feeding the clowns always win..I wouldn't rule out your Percs it looks like a bite mark to me and my clowns nip hard, hard enough to hurt me. He may have been molting when this happened and they are very soft at that point. JMO