cool completely.
Layering in jars: Place a row of red onions and carrots in the bottom of clean mason jars, then fit the fish pieces tightly on top. Repeat this layering until the top of the jar is reached.
Pouring and sealing: Pour the cooled, spicy vinegar marinade over the fish and vegetables so that it completely covers them. Seal the jars tightly.
Maturing: Place in a cool place (refrigerator or pantry) and let it mature for a few days so that the flavors can blend perfectly in the marinade.
