Combine cornmeal, flour, baking powder, sugar, and salt in a medium mixing bowl; mix well, and set aside.
Dissolve soda in buttermik in a small mixing bowl. Add egg, onion, and 1 1/2 teaspoons oil; stir well. Add to dry ingredients, mixing well.
Drop batter by tablespoonfuls into deep, hot oil (350°), cooking only a few at a time. Fry 3 minutes; turn and fry an additional 3 minutes or until hush puppies are golden brown. Drain well on paper towels. Serve immediately.