I like the ice chest idea. Also, the warmer the water the less oxygen it will hold.I have an old ice chest that has a hole drilled in the top of it for an aerator hose. Battery powered aerator to get it home, then an aquarium 110v aerator to keep alive overnight.
I’ve discovered two things. One can over-aerate a small space with a large aquarium model. Second, if the ambient air temp is too hot, the aerator will inject hot air into the small volume of water and make it too hot, killing the fish.