Method:
Preheat broiler. Toss catfish pieces with 2 tablespoons of olive oil and season with salt and pepper. Broil 4 inches from heat source, until cooked through, 6 to 8 minutes. Remove from oven and let cool.
In a large mixing bowl, combine fish with onion, bell pepper, mushrooms, olives, parsley, capers and paprika. Place in a glass or ceramic casserole or dish and add vinegar and remaining oil to cover fish. If fish is not covered completely, add a little more vinegar. Do not stir. Cover container with plastic and refrigerate at least 6 hours or overnight. Adjust seasoning and serve.