Combine mayo, pickle, lemon juice, and dill in bowl and mix until blended
Combine flour, beer, garlic powder, and pepper in a separate bowl
Cut lionfish fillets into strips
Heat oil in frying pan
When oil is hot, dredge fish through beer batter, covering the entire fish fillet
Put fish into hot oil and cook until the other side is golden brown
Place a paper towel on a plate to absorb excess oil and transfer cooked fish to plate
Serve with dill tartar sauce.