1 large red bell pepper
1 large orange bell pepper
1 large yellow bell pepper
2 tablespoons chopped scallions
2 tablespoons minced fresh flat leaf parsley
2 tablespoons capers
1 large clove garlic (peeled and finely minced)
1/4 cup extra-virgin olive oil (divided)
1 tablespoon golden balsamic vinegar
  pinch red pepper flakes (or to taste)
  Salt and freshly ground black pepper (to taste)
4 boneless, skinless mahi mahi fillet (6 ounces each)