Preheat oil in a deep fryer or large saucepan to 350°F.
This prepares the cooking environment for your fish.
In a medium bowl, combine the flour, cornstarch, baking powder, salt, and cayenne pepper.
Mix these dry ingredients well.
Gradually add water to the dry ingredients, stirring until the batter is smooth and lump-free.
Consistency is key.
Coat the fish pieces in the batter.
Ensure each piece is evenly covered.
Gently place the fish into the hot oil.
Fry until golden brown and crispy, around 5-7 minutes.