I have had 2 pistol shrimp in my tank for a few weeks, and this past week I added a Dracula goby who paired with my candy stripe pistol shrimp almost immediately. The next day I added a randal's goby, and put him right by the tiger pistol shrimp's rock (complete other side of tank). The randal's goby eventually just made his way to the Dracula/candy pair and started going In their hideout. I think they didn't like him in there, because he usually is out shortly after going in. What do I need to do to get the Randal's to pair with the tiger pistol shrimp?