Mix the 1 1/2 cups flour, salt, cayenne and seafood seasoning in a bowl until combined well. Slowly whisk in the beer. Whisk thoroughly to avoid clumps from forming. Set in fridge to chill.
A cool batter will be thicker and coat the fish better.
Lightly dust smelt with the 1/2 cup flour. Shake off any excess.
Heat oil in a large, cast-iron or other cooking vessel to 350 degrees.
Once all the fish have been dusted, submerge one by one into beer batter.
Carefully place battered smelt into fryer in small batches and let fry 4 to 5 minutes, turning until a deep golden brown.
Place fish on paper toweling and season with salt.