I say this with some guilt, but I got him. I caught the rock crab I've been after for almost 4 years. I believe he is behind the disappearance of several sleeping fish. I hope that's all of them as this was the 5th one I have trapped. He is so ugly.
One small glass jar, and one silverside rubber banded to a marble. Once he goes into the jar for the silverside, he can't climb out.
I just haven't been able to find him to position the jar near his hole. Tonight he finally showed himself.