These are shrimp/fish safe and are tiny dwarf crays. The picture probably makes them look bigger than they really are. They're only slightly larger than adult shrimp and a little stockier. Old amano shrimp (large) are bigger than these crays.
These little guys are incredibly cute. Sometimes, when I walk up to my tank to watch them, they'll see me and charge up in front and wave their claws at me. Lots of personality and I highly recommend them for anyone who wants some kind of interaction with their inverts. Shrimp and snails tend to just ignore their keepers but these guys will take notice of you. erv:
those are cool lookin but they're what, $20 each? whew. What does CPO stand for, btw, all I could find on a quick search was FS threads that didn't list the whole name.