Cut out 4 pieces of parchment paper, large enough to wrap one fillet each. Place on a large baking sheet.
Spread 3 lemon slices in the center of each piece of parchment. Top with tilapia fillets, carrot, dill, parsley and 1/2 tbsp butter. Fold one side of the paper over the fillet, then the opposite side, tucking it under the fish.
Bake for 20 to 25 minutes, until fish flakes easily with a fork.