Make gravy, brown flour lightly in salad oil.
Add minced onions and saute'until tender, add water slowly and stir until smooth.
Cut sausage into small pieces.
Break crab into small pieces.
Add sausage, crab and shrimp, also bay leaf.
Season to taste with salt and pepper.
Add oysters and cook until edges of oysters curl.
Add gumbo fillet if used.