I have a yellow watchman, and he spends all of his time in one cave structure at the front of my tank, they are very nervous, and will dart back in when people come to close. (when my neighbor's kids run up to the glass, for some reason thye can't find or see the goby
). I havent tried this, but he may feel more comfortable if he had a shrimp buddy. They naturally bond with glass shrimp (not ghost shrimp) in the wild, but those are hard top find (only seen them once, in SF) and I have heard of them pairing with pistol shrimp.