Make sure your grill is super clean. Any residue will cause the fish to stick.
Preheat the grill until it is very hot before putting the fish on.
Coat the fish very thinly with oil before cooking.
After you set the fish on the hot grill, leave it there! Don’t move it for at least a couple of minutes. This will give it time to sear and separate from the grill. When you do move it, wiggle it carefully and then roll it over.
David B. March 25th, 2011