Prepare Guava BBQ Sauce.
Thread fish, shrimp, and vegetables on skewers. Brush with olive oil; sprinkle with salt and pepper. Grill over medium-high heat (350° to 400°) 4 minutes. Turn skewers over, and brush with 1/4 cup sauce. Cook 5 minutes or until fish flakes with a fork. Serve skewers with sauce on the side.