Season catfish on both sides with Cajun seasoning and cook in 2 tablespoons of butter over medium high heat in a cast iron skillet for 3-4 minutes per side. Set aside.
Add the remaining butter to the skillet and cook the vegetables until tender. Stir in the cream cheese until melted.
Transfer the mixture to a mixing bowl and add the mayonnaise, Worcestershire sauce, and cheeses. Break up the catfish and gently mix it in. Add more seasoning to taste.
Spread the catfish mixture over sliced French bread and bake it at 350°F for 10 to 15 minutes until bubbly.