1-7 days is normal. It all depends on the fish. You may not even see it after 7 days as it come out when you are not around. Now, if you don't see it in 2 weeks you have a dead fish probably.
I'm not sure how much you know or your experience in this hobby but before you buy any fish do some research. I just type in google whatever fish I'm looking at while in the store and usually get live aquatias website for the description. It's not a bad place to start.