Found a crab

[jjthom2]

I found a crab in my tank, it's not hairy, but it has red eyes. I haven't stocked any thing yet so i'm not worried about him yet but I have a few questions;
- Is it possible for a crab to grow inside a small cavern until it is too big to get out? I ask this because I can see the crab and the entrance to the cavern and there is no way it would fit through.
-Are the red eyes a sure sign of a bad crab?
-What is the best way to catch it if it ever does come out?

 

[mrfipp]

The red eyes are not a sure sign of "bad crab" if you could get a pic and put it in the ID forum, maybe someone will know for sure. I suppose it is possible, but not likely that the crab would be literally stuck inside. You could always bust him out by breaking rock if you wanted to. If he does come out, put a food source in a small jar and then put a net over the mouth of the jar when he enters(or use your hand).