Slice the fish fillet into cubes.
Arrange the cubed fish in a bowl. Squeeze the lime over the fish. Mix well.
Add the onion and tomato. Mix
Add the Cilantro. Mix well.
Put the salt and pepper into the mixture. Continue to mix using a spoon until all the ingredients are well blended.
Cover the bowl with a plastic wrap and then place it in the refrigerator. Refrigerate for at least 3 hours (overnight is preferred).
Serve chilled. Enjoy!