In a ten inch heavy bottom saute pan, heat oil over medium high heat. Blend eggwash to ensure that egg, milk and water are well mixed. Dip catfish fillets into eggwash and then into flour, coating evenly on all sides. Saute fish, three fillets at a time, until golden brown, approximately three to five minutes on each side. Once cooked, remove and keep warm. In the same saute pan, add andouille, garlic, mushrooms and green onions and saute until vegetables are wilted, approximately three to five minutes. Add oysters and saute until their edges are curly. Deglaze with white wine, add heavy whipping cream and cook until sauce is slightly thickened. Season to taste using salt and white pepper. Once sauce has thickened, swirl in butter chips, two at a time, until all is incorporated. The butter will finish the sauce to a nice sheen. Place two to three ounces of oyster butter in the center of a serving plate and top with catfish fillet. Garnish with four cooked oysters per serving.