In the center of each piece of parchment paper, place an equal portion of fish. Season with salt and pepper. Place lemon and lime slices over fish. Place herbs over lemon/lime. Place 1 tablespoon of butter over herbs. Fold paper over into a triangle, fold edges over and secure with a stapler or paper clips. Place on a baking sheet and bake in a preheated 400 degree oven for 20 minutes. Combine tomatoes, onion, pepper flakes and olive oil. Season with a pinch of salt and pepper. When serving fish, open parchment paper, slide fish onto plates and top with tomato mixture.