If you use a stringer pop the stringer through its soft tissue on the bottom jaw. Not through the gills that is instant death for any fish. You can also use a cooler with an areator. When I take fish to the Sea Center that is how I transport them. I buy aquarium stones from walmart the flat bar style it creates alot more movement in the water.
About 4 years ago I had gone fishing with a buddy of mine on his boat at the end of the day we had caught only 1 flounder . He dropped me off at my truck at the walmart where we met up and I went on home. This was a Wednesday. On Sunday morning I met up with him to head out for another try and opened up the live well and our only catch from wed was still in the live well and ALIVE. I would not have believed it if I hadn't seen it. It was in the fall so it was cool and the water in the live well stayed cool.
SORRY Off subject but the question just reminded me. Resilient fish.