Fish Two O'clock Bayou

Combine the salt, cayenne and black pepper. Take a rounded 1/2 teaspoon and sprinkle it over both sides of the fish. Let stand 1/2 hour. Reserve remaining salt and pepper mixture.
Heat the butter in a large skillet over high heat until it is half melted. Add onions, celery, bell peppers and the remaining salt and pepper mixture. Cook about 2 minutes, stirring occasionally.
Add the flour and 1/2 cup of the stock and stir until well blended. Reduce heat and simmer until liquid is almost evaporated, stirring frequently.
Stir in remaining stock. Add fish in a single layer and sprinkle green onions over the top. Cover and cook just until fish is cooked, about 5 minutes. Serve immediately.