It's been about six months since I added a watchman goby to my tank that has a candy stripe pistol shrimp and they haven't paired up. I was really looking forward to seeing their interactions. Do you think if I added another pistol shrimp it might pair with the goby or would the pistols fight? Or is it the goby that's the issue and I should consider a second goby? Tank is 55 gallons in display. Thanks.