Pour oil into large heavy skillet, filling no more than 1/3 full. Heat to 375 degrees on medium heat.
Mix Batter Mix and seasoning in medium bowl. Add beer, stir until smooth. Dip fish into batter. Shake off excess.
Fry fish, a few pieces at a time, 3 to 5 minutes or until golden brown, turning once to brown evenly. Drain on paper towels.
Yogurt Sauce
In a medium bowl, mix together yogurt, mayonnaise and sour cream. Stir in fresh lemon juice until consistency is slightly runny. Season with jalapeño and spices and serve with cod.