Look for a Randall's pistol shrimp and not a Tiger. The Randall's stay smaller, plus I think they look a little better too. My YWG and Randall's get along nicely. They have circled around the tank a few times, so make sure your rock work is nice and secure to the glass and you'll be fine. Mine even made it's burrow next to the glass for a while, so it was fun to watch them do their thing.