Shrimp can live in anything, really. They need an air pump and frequent water changes, but other than that, they can live in just about anything. 5gal aquariums work quite well for a colony of RCCs. Ghosts can live in about anything, as they generally dont breed. The RCCs will keep their colony up in number if given enough room. I would highly suggest the RCCs over the ghosts/grass if you plan to breed and raise your own food. Very well worth it as you have to quarentine for a month before feeding anyway. In that time, you will most likely have a bunch of gravid females that will hatch young. But any fish will eat the babies, so shrimp only if you plan to breed.
Mark
Mark