Make beer batter by whisking together the flour, baking powder, paprika, garlic powder, onion powder, and salt in a large mixing bowl. Pour in the beer and whisk until a smooth batter forms. Cover bowl and refrigerate until ready to fry fish.
In a small shallow bowl, prepare the dredging mixture by mixing together the flour and salt. Set aside.
In a heavy-bottomed pot over medium high heat, add enough oil to fill up 2/3 of the pot. Heat oil to 375F. Use a deep fry (kitchen) thermometer to help monitor the temperature of the oil.
As the oil heats up, place a wire cooling rack over a paper towel lined baking sheet. Set aside
Thoroughly, pat dry the fish pieces. Working with one piece of fish at a time, coat in dredging mixture and shake off excess flour. Transfer into bowl with the beer batter.
Using your hands or a fork, thoroughly coat the fish in the batter and allow excess batter to drip off.
Carefully, add coated fish into heated oil. Working quickly, repeat with remaining fish frying only a few pieces at a time. Use a deep fry (kitchen) thermometer to make sure that the temperature of the oil is maintained at 375F. If oil temperature drops below 375F, allow the oil to heat back up before continuing to fry remaining pieces of fish.
Fry fish pieces for 5-6 minutes, turning halfway through cook time. Fully fried/cooked fish should be richly golden brown in color.
Transfer to wire rack and season with coarse salt and black pepper (optional). Serve immediately on its own or with tartar sauce, fries and lemon wedges.