Finely chop the shallots and garlic.
Heat the oil in a large frying pan and gently sauté the onion and garlic. Add most of the turmeric and paprika, stir for 30 seconds.
Rinse the spinach leaves and add to the pan. Pour over the lemon juice and stir through. Put the lid on and cook for a minute, until the spinach begins to wilt. Place the fish on top, season with salt and pepper and sprinkle the remaining turmeric and paprika over them. Put the lid on and steam over low heat for about 5-10 minutes (this depends on the thickness of the fillets).
Serve the fish with the spinach.