In a shallow bowl, mix together the flour, paprika, garlic powder, salt and pepper.
Dip each fish fillet in the flour mixture to coat.
In a large skillet over medium heat, melt the butter.
Add the fish fillets and cook for 4 minutes on each side or until golden brown and cooked through.
Remove from heat and set aside.
To assemble sandwiches, place one cooked fish fillet onto each bun bottom. Top with desired toppings. Place other bun top on top of sandwich and serve warm.