I had a bunch of blue legs in my tank and then one by one they started dying. I talked to my LFS and they asked me to see if I had a brown and white legged hermit. I started looking and found it by watching it yank another blue leg out of its shell and kill it. My LFS said that brown legs are more aggresive and tend to kill off blue legs. But, anyway that was what mine looked like and they identified it as a brown legged hermit.
just my 2cents worth