Boil the shrimp for a couple of minutes.
Chop the onions into fine julienne strips, place in a cup with water and a little salt. Let stand for 5 minutes. Peel the tomatoes, cut them into small pieces. Chop the chili pepper in small squares.
In a bowl put all the ingredients, salt and pepper. Squeeze the oranges and lemons, add the juice and fish stock to the previous mixture.
Let stand in the fridge for 3 hours.