Combine garlic salt, paprika, onion powder, oregano, black pepper, cayenne pepper and thyme. Rub mixture on both sides of fish.
Heat a large cast iron skillet over medium high heat. Spray skillet with nonstick cooking spray and add fish. Cook 8 to 10 minutes on each side, or until fish flakes easily with a fork.
Recipe Note: Cooking times may differ depending on the thickness of the fillet or steak.