I was doing some cleaning in the sump tonight and noticed something alive on one of my sump rocks - a closer inspection revealed a small crab. Its body is about the size of a dime. Sorry, no picts - I tried to get one with my phone but it was quickly gone. 
 
What is the generally accepted opinion:
A. Let well enough alone? 
B. Capture and remove?
C. Pretend I never saw it? 
