Lemon-Batter Fish

1-1/2 cups all-purpose flour, divided
1 teaspoon baking powder
3/4 teaspoon salt
1/2 teaspoon sugar
1 egg, beaten
2/3 cup water
2/3 cup lemon juice, divided
2 pounds perch fillets or walleye fillets, cut into bite size pieces
Oil for frying
Lemon wedges, optional 

In a shallow bowl, combine 1 cup flour, baking powder, salt and sugar; set aside. 
Combine the egg, water and 1/3 cup lemon juice; stir into dry ingredients until smooth. 
In separate shallow bowls, place remaining lemon juice and remaining flour. 
Dip fillets in lemon juice, then flour and coat with the batter. 
Heat 1 in. of oil in a skillet. 
Fry fish, a few at a time, over medium-high heat for 2-3 minutes on each side or until the fish flakes easily with a fork. 
Drain on paper towels. 
Garnish with lemon if desired.