Originally Posted by
chgoeditor
Another tip for keeping whole fish from sticking to the grates -- cut thick onion rings and toss them in oil, then put them on the grate and the fish on the onions. It elevates them a bit and the fish won't stick to the onions.
I think the trick is to make sure the grates are very hot, but the fire is only medium. I let the kettle come up to temperature and then cooked the fish direct over the coals with the lid on which kept the fire under control. I also made sure the grates were really clean and then well oiled – as was the fish.