Heat grill to medium-high heat. Arrange fish on a rimmed baking sheet; brush 1 tablespoon of the oil over both sides of fish. Sprinkle salt and pepper over fish.
In a small bowl, toss pepper strips with remaining olive oil to coat. Grill peppers turning once, until light grill marks appear, about 2 minutes per side. Transfer to a platter or rimmed baking sheet and keep warm.
Grill fish on covered grill 3 minutes per side or until fish is opaque in center. Arrange peppers on four warmed dinner plates. Place fish over peppers; top with olives.