What can kill a blue knuckle hermit crab?

[Ace1]

i just lost a blue knuckle, found on the opposite side of the tank out of his shell. His shell was on the other side of the tank empty.

When i wen to move it claws fell off..

what

 

[dc]

Is this in a fish tank or a land hermit? Your profile says you don't have a tank.

 

[Opcn]

was it a molt you found perhaps?

 

[TankFabricator]

What are it's tankmates?

 

[TFM]

Ace1,

Water quality changes can cause Hermits to crawl out of their shell and die. I've seen it occur most during salinity changes. I'm sure pH and Alkalinity are a big factor here as well.

Was the tank cycled? If it wasn't cycled, a Ammonia or Nitrite spike could have easily killed him.

Don't lose hope - as others have said it might just be a molt. Keep watching the shell. After molting, a Hermit crab is soft and vulnerable. While their exoskeleton hardens, they often hide or/and stay in their shells.