Preheat oven to 425. Place wire rack on baking sheet and spray with cooking spray.
Mix panko bread crumbs, garlic powder, 1 teaspoon salt, and 1 teaspoon pepper in a shallow dish.
Optional: If you want the fish to brown a little more then toast the bread crumbs: Heat olive oil in a skillet on medium high heat and add bread crumb mixture. Saute until toasted brown and scoop back into the shallow dish.
Place buttermilk in another shallow dish (I use pie plates or cake pans). Season the fish on both sides with additional salt and pepper. Dip fish in buttermilk then dredge in bread crumbs.
Place fish on wire rack. Bake for 10-12 minutes until fish flakes easily with a fork. Serve immediately.