Make the salsa by placing the mango, red bell pepper, jalapeno, red onion, lime juice, cilantro, salt, and pepper in a salad bowl. Toss to combine and chill in the fridge while making the fish.
Make the marinade: whisk together the oil, lemon juice, parsley, garlic, oregano, basil, red pepper flakes, salt, and pepper in a shallow dish. Add the tilapia filets, toss to coat, cover with plastic wrap, and refrigerate for 30 mins.
Heat a grill or grill pan over medium-high heat and grill the filets for 3 to 4 minutes on each side, or until fully cooked. Serve with mango salsa on top.