I have a Yellow Watchman Goby (juvenile) that is without a pistol shrimp. Have been observing its behaviour. I have white glove shrimp (rock-pool shrim) in with it. The Goby tries to pair up with these shrimp and lead them back to the goby's hole. I can only assume that the goby is trying to lead its new found frend home..............I can just imagine it saying , mummy, it followed me home :-)
Will have to keep on the look out for a pistol to pair with my goby. From what I have read, the tiger pistol shrimp (Alpheus bellulus) is the shrimp that the yellow watchman goby most assocated with.