I'll take a whole fish and make a fillet out of it, cutting off all the fins and tail. Wash, dry with a paper towel and cut into pieces about 2.5-3 cm wide. For this amount of fish, I will take only 1 St l of soy sauce. Marinate, a little sprinkled with pepper pieces-Cayenne. You can pepper the fish with any pepper you like. If there will be children, do not pepper. I'll cover the dishes and make the batter. Pour 2 tablespoons of kefir into the dish and extinguish a little of the baking soda in it. Break the egg, working with a fork, connect the mixture. Add flour and mix each spoon. The batter should have the consistency of thick sour cream. Add salt to taste, not forgetting the soy sauce. Heat the pan. I'll use a non-stick one and just put a little oil on it. Fry the Pollock pieces on both sides over medium heat for a couple of minutes, dipping them each in the batter, skewering them on a fork.