The seller should be able to give you full information, including a shipping number so that you can track the package.
Failing that, the shipping company should be able to give you a good idea of typical shipping times.
You really need an accurate arrival time and date so that you can be available to accept the package and unload the fish.
It isn't the same for all. Most sellers don't sent fish out one at a time but wait until they have several orders so they can ship to the US in one package. Sometimes it takes a month; sometimes less; sometimes more. Julie should be able to give you the most accurate information.
Are you worried because you haven't received an ordered fish?