Rinse and dry the filets heat oil. Remove bones. Slice the fish into chunks. Season the fish and coat with cornstarch. Allow to rest 5 minutes. Cook the pineapple chunks in butter and season. Mix the 1/4 cup pineapple juice and cornstarch. Add cup of juice and boil. Add thickener. Still till it coats a spoon it's ready. Fry fish and move to paper towels to absorb excessive amounts of oil.