Cook pasta according to package directions, omitting salt and fat. Drain. Set aside and keep warm.
Heat 1 tablespoon oil in a large nonstick skillet over medium-high heat. Add shrimp and scallops to pan; sprinkle with salt. Sauté 3 minutes or until almost done. Remove shrimp mixture from pan.
Heat remaining 1 tablespoon oil in pan over medium-high heat. Add onion, garlic, fennel seeds, pepper, and pancetta to pan; sauté 1 minute. Stir in tomatoes; bring to a boil. Cook 2 minutes, stirring occasionally. Return shrimp mixture to pan; cook 1 minute or until thoroughly heated. Remove from heat. Serve shrimp mixture over pasta. Sprinkle with basil.