Fillet, skin and dice raw fish. Place in a glass bowl; pour lemon or lime juice over it and marinate for 3 hours, turning fish pieces with a wooden spoon from time to time, so that juice turns the fish snowy-white and non-transparent. It will look and flake like cooked fish.
Dice the tomatoes and add to the fish. Add diced green pepper to fish mixture with olive oil, parsley, vinegar, Tabasco, oregano and salt and pepper, to taste. Serve chilled, garnished with diced avocado pear and sliced stuffed olives.