mysterious hermit crab death

[mmm55645]

I couldn't find my hermit crab and after looking for him, I saw his severed legs and front body on the substrate. His shell was on a rock above his body. The hermit was one that had blue legs.

I am wondering if his death was natural or if something else killed him. It looks like something was nibbling on his body, but I don't know if the nibbling was postmordem.

My 55g tank is lightly stocked with only 1 mithrax crab(1/2 wide), 1 watchman goby(1.5" long), 2 zebra turbo snails, 1 small red hermit, 2 astrea snails and lots of worms.

If the crab died of natural causes would he fall out of his shell or if something else killed him would he be pulled from his shell?

I wonder if the mithrax crab could have done it. I also wondered if perhaps he was molting and was looking for another shell, which at this point I do not have in tank.

Water parameters are in check, so it wasn't poor water quality that killed him.

 

[hermitage]

I'll bet it was another crab. I have a similar mix and occasionally find the same thing. Crabs like to fight.

 

[DLANDINO]

I am having the same issues on my reef. I am thinking it is due to the lack of suitable large shells for the hermits to go into when they are out growing their current. I am not adding more shells and letting nature take its course. I have heard some bad stories about hermits and corals, a venture I am about to get into.

 

[TheMcs]

There is also a chance that the crab molted (and you are seeing the molt, which other inverts will eat) and also changed shells. Are there bigger shells that it could have moved into? Usually after molting inverts will hide for a while, due to the fact that their shell is soft (ever eat soft shell crabs?) and their defenses are down.

 

[CSMReef]

I agree with the crab molting / switching shells scenario.

 

[mmm55645]

There were no extra shells in the tank, unfortunately. The hermits shell is empty in a rock.

 

[TheMcs]

Are you positive it's empty? Hermit crabs can pull themselves very far in given the room, which would be likely with a fresh molt.

 

[Bremmon]

Just a couple of days ago, my wife calls and says that our blue-legged crab was dead. He had been looking pretty lethargic several days before.

She said the shell was empty.

Then she called about 30 minutes later and said that the crab had molted and was back in his shell.

Might want to check around if you haven't already. I don't know what happens if a crab molts and doesn't fit into the shell it had been living in up to that point.