Fish ship around the world in bags, most able to withstand atleast 3 days w/o any issues, and many even longer. I often buy fish out of town and drive 4 hours or more with them. When I shop out of town, I let them know I'm traveling and ask them to use plenty of water and oxygen in the bags, and also request a styroform cooler. They have them on hand because their shipments come in them. If I was just buying a couple fish though I'd bring my own cooler. The last time I did this I was buying a large expensive angel and they wanted to put some sort of additive in the bag, a bag buddy or something, which I refused. I think it's best to stick with water and control the temp.
Speaking of crays, the only fish shipment I ever had get misrouted was crays. Cajun crays actually. They were in teeny tiny bags, smallest I've ever seen, and when I received them on day 8 of their journey they were still in fine shape. Just hungry! I wouldn't expect most fish to survive that trip, but crays are really hardy and excellent shippers.
