Season the outside of the fish well with salt.
Place fish onto grill and leave to cook, undisturbed, for 6-7 minutes, until the skin is charred, crisped, and fully cooked on one side. When the fish is ready to flip, the skin will release easily from the grill surface. Gently flip the fish using tongs and a metal spatula. If the fish sticks, don’t force it. Wait another minute or so and then try again.