Thaw the fish, clean it of entrails and scales, then cut it into small pieces. Peel the onion and cut into small half rings. Heat a frying pan with vegetable oil. Peel the garlic and chop into small pieces.
Add all the necessary spices and chopped garlic to the hot oil in the frying pan, stir and keep in the frying pan for about 1 minute.
Salt the fish, add chopped onion, stir and pour in oil with garlic and spices.
Toss the fish with the oil and onion and let it simmer until the fish pieces turn pale. Place on serving plates and serve.
Garnish the resulting appetizer with fresh herbs, such as dill.