I've seen fish survive for over a week in transit. I had a pair of adult platies sent to me on September 10, 2001, and obviously with the 911 attack, that package did not arrive on time. It didn't arrive until the 19 of September, and the fish inside were perfectly alive (though a little ammonia burned) They healed up in a day or so and were absolutely fine. I'm not recommending that we start shipping our fish UPS ground or anything like that, but it's good to know how long they can last. Just make sure you pack them correctly (IMO, just enough water to keep them suspended, and as much air as possible) and they should be fine for a lot longer than we may expect. (And obviously, the individual fish species, and it's hardiness is a HUGE factor)
The biggest issue with fish dying in transit is not air as much as it is temperature. Don't leave your bagged fish in the closed car while you run errands or anything like that. Avoid extremes in temperature, and get them home as soon as possible, and they should be fine.
If you know it's going to be a while, you can always ask the clerk to pour out some of the water (they always use to much, in my experience) and replace it with air. Don't mind the funny look they give you.
The biggest issue with fish dying in transit is not air as much as it is temperature. Don't leave your bagged fish in the closed car while you run errands or anything like that. Avoid extremes in temperature, and get them home as soon as possible, and they should be fine.
If you know it's going to be a while, you can always ask the clerk to pour out some of the water (they always use to much, in my experience) and replace it with air. Don't mind the funny look they give you.
They were individually bagged with air and looks like they made a trip about 20 hours (give or take).