Strange Hermit Crab Issue

[rubikcube]

I bought 5 blue leg hermit crabs for my tank about a week ago. Since then, I've found two dead ones out of their shells. The strange part is that I still have 5 crabs alive and in their shells. I've triple and quadruple checked this. My tank is fairly new and I've never had hermit crabs in there before this. Any ideas on what is causing this? My water parameters are:

Nitrate: undetectable
Nitrite: undetectable
Ammonia: undetectable
pH: 8.2
Phosphates are a little high as is evidenced by some hair algae growth. Probably from the frozen food.

 

[Brodie]

Hermit Crabs molt.

 

[tripper]

Brodie is right. Hermit crabs will molt and what you are seeing is their old exoskeleton in the tank. Many times it is hard to tell if it is a dead crab or not. You will notice a small split towards the back of the body which is where the hermit pulled out of the old skin.

tripper

 

[rubikcube]

Ahhh, that makes perfect sense. I can't believe I didn't think of that before.

 

[Stuart]

It is scary the first time you see a molt case - it looks so like a dead one.

 

[Brodie]

It does, you just sit there and ponder how it died. I used to think I was losing hermits left and right.