In a small bowl or jar with a lid, make the spice blend. Mix together the paprika, onion powder, garlic powder, white pepper, black pepper, cayenne pepper, oregano, thyme, celery seed and kosher salt. Coat the fish fillets with the spice mixture, and allow to sit at room temperature for no longer than 30 minutes.
Heat a heavy skillet over high heat. Add oil, and heat until it is almost smoking. Place the fillets in the pan, and cook for about 3 minutes per side, or until fish is opaque and can be flaked with a fork. Remove from the pan, and place onto slices of white bread. Pour pan juices over them and squeeze lemon juice all over. Do not underestimate the white bread. It gets quite tasty soaking up all the juices.