Roll catfish cubes in flour mixture to coat and shake off excess.
Heat butter in a large pot over medium-high heat until melted and bubbling.
Stir in catfish; cook about 20 seconds per side.
Stir red onion, sherry wine, oysters with liquid, and Worcestershire sauce into the catfish and butter; heat just to boiling, 5 to 7 minutes.
Pour the cream into a small bowl. Ladle about 1/4 of the hot liquid from the pot into the cream; stir to heat the cream evenly. Pour the cream mixture back into the pot; stir. Continue cooking until heated through, being careful not to bring the mixture to a boil, another 5 to 7 minutes.
Ladle into bowls; top with fresh parsley and black pepper to serve.
336.55 calories; 15.54 g protein; 19.44 g carbohydrates; 0.6 g dietary-fiber; 0.56 g sugars; 21.18 g fat; 9.28 g saturated-fat; 117.97 mg cholesterol; 718.83 IU vitamin-a-iu; 4.59 mg niacin-equivalents; 0.18 mg vitamin-b6; 5.16 mg vitamin-c; 34.83 mcg folate; 80.18 mg calcium; 6.92 mg iron; 63.19 mg magnesium; 385.71 mg potassium; 672.7 mg sodium; 0.21 mg thiamin; 190.65 calories-from-fat; 22 percent-of-calories-from-carbs; 55 percent-of-calories-from-fat; 18 percent-of-calories-from-protein; 24 percent-of-calories-from-sat-fat