One of the last times I moved large fish (a pair of haitiensus, male about 15"), we put a 100 gal rubbermaid stock tank in the back of an SUV, put enough tank water in to cover the fish, dropped them in, and drove the 80 miles to Chicago.
Had to use a landing net to catch them.
You might want to check at a fish market, for one of those large styros they ship fish like salmon in, the have a lid to tape on tightly.
They made the trip just fine. Moved the glass tank separately (of course).
I moved a large blue and white koi another time, trying to use a 5 gallon bucket, when I got to my destination, it was laying on the car seat next to the bucket, but it lived anyway.