I just got some ghost shrimp at PetSmart and brought them home, I looked in the bag before I put them in. One is pregnant, the problem is that shrimp is it has a big "~1 inch" long brown tube coming off its back. Where the tube is a slight to medium hump on its back. What is that tube? Should I be worried about infecting my tank with what ever it is? Also, will black mollies eat shrimp?