Place the diced fish in a bowl with lemon juice covering the fish and place in refrigerator, covered, for one or two hours.

Preheat oven to 400 degrees Fahrenheit.

Meanwhile, rub the beets with a bit of oil, sprinkle with salt and place them in a baking dish. Cover well and roast in oven for one hour. Peel and dice when done, let them cool completely.

Strain the fish, discarding all the lemon juice, and put into a mixing bowl. Add all remaining ingredients and mix well. Let sit 10 minutes before serving.