So I was at my lfs and I saw some crayfish for only $1.50. All of my fish pretty much only swim at the top level of the tank besides my pleco which is about 7.5 inches and sometimes hangs on the bottom. I've always had a fascination with inverts/critters and would like to have one and these look pretty cool (not willing to spend 25 on a blue lobster which are basically the same from what I understand). I have some good cover for him, and the tank is a decently tall (40g hex front) so I doubt it would get anywhere near my fish. What are the deal with these? What to feed them? How to feed them? Will they still get my fish? Are they a good idea? What if in the future I wanted to add a small crab/adf/rope fish/loach/dragon goby/shrimp kind of thing? Actually to expand on that. What 2,3 or 4 of these critters would be compatable with each other if any would be at all. Thanks, I appreciate the input.