i would put the Pistol Shrimp in a breeder box in the DT. As for the Goby, personally, I don't quarantine fish just for observations. If you are, that's fine but I don't know that you'll be able to learn much about him unless you plan on keeping him there for more than a month, at least. Gobies are very susceptible to internal parasites and I would treat him prazipro. These parasites, for obvious reasons, can go unnoticed for longer than your quarantine period. Do you have a particular place in the tank that you would like the pair to settle or does that not matter? If you have a preference, once ready to add both fish and shrimp to the DT, then (after acclimation) you could place them where you want them and they will most likely stay. You can do this by sliding them both down an uplift tube (used for freshwater under-gravel filters). You could also net them and do the same but they sometimes are less cooperative when trying the latter IME. They are a very rewarding combination to have and a crowd favorite when visitors come by. Good luck!
