Why do my hermit crabs not survive?

[ewm]

I have a 30 gallon fowlr that has been running for 7 months. I have five fish, a shrimp, several snails and hermit crabs in the tank.

Everything has been doing great... except for the hermit crabs. They just dont see to survive very long. I have tried adding them on a couple of occasions and they seem to always dwindle down to just one or two left.

The fish I have are two clowns, a cardinal, six line wrasse, and diamond watchman goby.

Any advice?

 

[nmotz]

Do you have extra shells of slightly larger size for them to upgrade? Also, are the shells of the same type of snail that they currently live in? If the answer to either of these is no, then your hermit crabs are fighting to the death over the lack of available "living space."

 

[ColoReefer970]

6 line wrasse is slaughtering them?

 

[ewm]

I do have extra shells and I have two different kinds of snails, one of which has the same shell as the hermit crab that is missing today.

 

[nmotz]

hmmm, maybe you have a hitch-hiking mantis?

 

[LQT]

I'm thinking the sixline is doing them in.

 

[ColoReefer970]

No joke...I had one murder an entire CUC before I could catch it...he killed at least 100 snails