Use a fillet of one of the listed fish or you can use a sliced fish, with the pieces being no larger than 6″ (15 cm). Salt the fish well and sprinkle it with black pepper.
Boil 4 1/5 cups (1 liter) of water in a pot, with the slightly cracked allspice, rosemary. Put your steamer basket on, place the fish in it, cover and allow it to boil for about 10 minutes.
Then, carefully remove it, top it with olive oil and serve with a slice of lemon and a side dish of vegetables, if desired.