Recently went to Seattle and bought salmon at Pike Place Market. Received a boxed styrofoam cooler with "blue" ice packs. I was told by the market people that it would have to be checked as luggage.

Bought day before (around 3pm) for a 6am flight SEA-IAH-LGA and fish came back home nice and cold and fine and dandy. Granted the box has the fish market name on it and I am sure SEA TSA sees a lot of it.

Fish was opened that night and was cold and not fishy.

YMMV

- HF