Rinse fish off with cold water and pat dry with paper towels. Remove as much moisture as possible. Cut each fillet in half.
Preheat grill for high heat. Once it comes up to temp place skillet on the grill.
Combine seasonings and spread out on to a large plate. Dredge fillets into blackening spices. Season both sides and set onto a clean dry plate or pan.
Add olive oil and butter to heated skillet and wait for it to smoke a bit. Carefully place fish into pan and cook for 4-5 minutes side, depending on thickness. Be very careful turning the fillets as fish can be quite delicate and prone to breaking. Reduce heat to medium if needed.
One internal temperature of fillets reach 145 degrees F., remove fish from pan and place onto a paper towel lined dish. Serve with lemon wedges and your favorite sides.