Fish may be alive after 2 days or more, but each day lessens the chance of live arrival.
Plecos have a sharp spine, so each hour hastens the chance of a pierced, dry bag.
The bast carrier is the one that provides and guarantees the fastest service to whatever city.
I have used the US post office, and Fed Ex and had good and bad experiences with both.
With the post office, if they guarantee arrival by a certain time, and it is late, you get the shipping fee back.
The best is airport to airport, but that has a set up process that is really only worth it for commercial shipping. With airport to airport, fish can arrive in as little as a few hours.