I have always heard that a good boat that is water tight you can find spiders in the bilge. I have been working for 4 years to seal up and redo opening top side to my boat and I think that it finally paid off. We had a very heavy rain last night and more rain to day. I haven't set up my auto bilge pump yet so after every rain I have to go check out the amount of water in the bilge. Well when checking a dry bilge to day I found a spider in there. It made me very happy to finally get to that point.
Congrats on your new little friends!
I guess fish in the bilge would be bad thing!