Rinse fish, scallops, and shrimp; pat dry with paper towels.
Preheat oven to 450 degrees F. Divide fish, scallops, and shrimp among four 10- to 12-ounce au gratin dishes. Add zucchini, squash, and shallots; sprinkle with salt and pepper. Whisk together oil and wine; spoon over mixture in dishes. Sprinkle each with herb.