Bottom feeders dying (killed)

[Form Blazing Sword!]

I have a 125 gallon tank. Coral beauty, two Mia Tia's, yellow fin chrome, hippo tang, and wrasse (rainbow?), urchin. I need a bottom feeder. I've used blue, red, and yellow hermit crabs. Even goby's. They all end up getting killed. I'm pretty confident that it's predominantly my wrasse. What type of fish, crab, etc. Would withstand or stand up to the wrasse?

 

[Misled]

I always liked cucumbers.

 

[Timfish]

Just to be certain, when you find the bodies you're not tossing out the shells? Because when crabs molt they may stay hidden inside their shell for a day or two. A big hermit like a thin stripe or speckled hermit.

 

[Form Blazing Sword!]

I leave the shells in the tank. I was thinking of a larger hermit as well. They are tough and I think the occasional hit could be easily absorbed. The cucumber that @mismentioned I think is a good idea as well. I just don't know if the wrasse would mess with it. My wrasse is very curious about anything that goes into the tank (including my arm when cleaning)