How to keep fried fish warm and crispy during transport to venue?

For crispiness: keep the fish on a cooling rack and well ventilated no matter what - even when using steam tables, which should be fine for this purpose.

For warmth: I have no idea how the fish will fare depending on how you transport it, but do not let the time between cooking and eating be longer than two hours unless you can reheat the fish with a fryer or oven that gets hot enough for long enough to get out of the danger zone of 40-140 degrees Fahrenheit.

Fried foods neither hold nor transport well. They are best served directly from the frier. If they do need to be held, a slow oven which will keep them dry (by allowing steam from the food to leave) is the best way.

There simply is no good way to hold, transport, and serve fried foods that will maintain the crispy quality. Think of every delivery meal you have ever ordered of mozeralla sticks, chicken fingers, or even just plain french fries. They simply are not the same as at the restaurant.

If you absolutely insist on serving fried fish, the best way to transport it would be in a single layer, in an insulated container, lined underneath with paper towels to absorb some moisture, and with vent holes so that at least some of the steam can escape instead of condensing back on to fish and making the breading even soggier.

You could improvise such a container with plastic or foil takeout containers, punching (fairly large) holes in the top, and using blankets or towels underneath and around the sides as insulation. Make sure you leave the ventilation holes uncovered, so that the steam can escape.

Still, you will have tension between keeping the food hot, which requires no holes and lots of insulation, and keeping it (somewhat) crispy, which requires allowing free air circulation, but would cool the food faster.

In the end, this is a situation where choosing another item, one that is friendier for holding and transporting, will serve you better.

Poaching the fish would be ideal, as would creamy or saucy dishes with the fish as an ingredient instead of the featured player.

Have an empty cool steam containers or aluminum foil pans, place in the vehicle. place the fried fish ontop of a wire rack right out of the oil. when all done, place fish in paper bags. place wire rack in the cool aluminum foil pan or steam tray, place hot fish out of the paper bags, then place fish ontop of rack. Cover fish on a rack with paper, paper bags or wax, or parchment paper.

when you arrive, place fish in paper bags to carry inside, have your warmers set up to be hot. Place the racks inside, then take fish out of bags and place on rack, then cover again with paper. fish should stay crispy and warm

Fry up all of your fish ahead of time. When you arrive have that fish put into an air fryer or counter top convection oven that you keep to perk up crispness on on your truck/ mobile kitchen. If you do not have a deep fryer on your truck you can prep everything, bread it, and then bring just the fish on the premise.

As a piece of fish is done, add it to the sides/meals and/or a chafer lined with lots of paper towels ... no top goes on the chafer unless it has perforated holes. It works best and beautifully we have done it many times for old fashioned fish fry.