Cook the fettuccine pasta according to package instructions until al dente. Drain and set aside.
In a large skillet, heat the olive oil over medium heat. Season the salmon fillet with Cajun seasoning and cook for about 4-5 minutes on each side, or until cooked through. Remove from the skillet and flake into bite-sized pieces.
In the same skillet, melt the butter over medium heat. Add the minced garlic and sauté for about 1 minute until fragrant.
Pour in the heavy cream and bring to a simmer. Stir in the Parmesan cheese until melted and smooth. Add salt and pepper to taste.
Add the cooked fettuccine, lobster meat, crab meat, and flaked salmon to the skillet. Toss everything together until well combined and heated through.
Serve immediately, garnished with chopped parsley.