Peel mangoes and pit. Cut pulp into thin slices or wedges. Arrange on a plate and sprinkle with mayonnaise.
Rinse and pat dry smelt, season with salt and pepper. Beat eggs in a bowl. Coat fish with flour, dip into eggs and coat with almonds, pressing well.
Heat plenty of oil (about 600-800 ml) (approximately 2 1/2-3 cups) in a large skillet or deep fryer and cook fish, few at a time, until golden brown on all sides. Drain on paper towels and arrange on top of mango. Serve.