In a medium bowl, combine the flour, cornmeal, baking soda, baking powder, and salt. Whisk until well mixed.
Slowly pour in the ginger ale while whisking, until the batter is smooth and free of lumps. The batter should be slightly thick but still pourable.
Heat the oil in a deep-sided skillet or fryer to 350°F (175°C). Make sure the oil is deep enough for the fillets to float while frying.
Dredge each fish or chicken fillet in the batter, letting any excess drip off.
Carefully place the battered fillets into the hot oil. Fry for 4–6 minutes per side, or until golden brown and cooked through. Fish should flake easily with a fork; chicken should reach an internal temperature of 165°F (74°C).
Remove from the oil and drain on a paper towel-lined plate to remove excess oil.
Serve immediately while hot, with tartar sauce, lemon wedges, or your favorite dipping sauce.
Enjoy!