In a small bowl place the stick of butter and micowave it on low for a few seconds till the butter becomes fluid. Add the garlic powder,lemon pepper and salt to the butter and mix well. Turn on the barbecue to medium and place a sheet of tin foil across the grill. Cut the steelhead fillets into quarters and remove the skin. When the grill has become hot, brush a little of the butter mix onto the tin foil and add fish quarters. Brush the fish with the butter mix every few minutes or until it is all used up. Fish should be cooked in about 12-15 minutes.