Cut the fish into ½-inch cubes and place in a deep bowl; Add the lemon juice and stir until the fish is covered with the lemon juice. Cover the bowl with plastic wrap and leave in the refrigerator. chill until fish is opaque, about 1 hour.
Meanwhile add the onion, garlic, coriander and olives with the tomato sauce and mix well; After time in the fridge, mix the fish with the other ingredients, stirring carefully until the fish is well covered with the sauce; Serve cold adding Zambos Ceviche platanitos as accompaniment.