Heat butter and oil in a 6 to 7-quart stock pot over medium-high heat. Add onions
, pepper, and garlic and saute for 5 minutes, until softened and slightly caramelized. Add gumbo powder, bay leaf, cayenne, paprika
, salt, thyme
, oregano and pepper and continue cooking, another minute. Add tomato paste and cook until it browns, another 4 minutes. Add seafood stock, bring to a boil then reduce heat and simmer 30 minutes. Right before serving, add haddock and continue to simmer
for 5 minutes, then add remaining seafood
. Cook another 5 minutes. Add hot sauce
, and season with salt and pepper, to taste. Serve over rice and sprinkle with file powder.