Start by seasoning the defrosted halibut fillets with smoked paprika, oregano, garlic powder, onion powder, chili flakes, salt, and pepper. Let them sit for about 10 minutes to absorb the flavors.
In a large pot of salted boiling water, cook the pasta according to package instructions until al dente. Drain and set aside.
In a large skillet, heat the neutral oil over medium heat. Add the minced onion and bell pepper, sautéing until they are softened and fragrant, about 4-5 minutes. Add the minced garlic and cook for an additional minute.
Stir in the fire-roasted tomatoes and stock (or water). Bring the mixture to a simmer and let it cook for about 5 minutes, allowing the flavors to meld together.
Push the vegetable mixture to the side of the skillet and add the seasoned halibut fillets. Cook for about 3-4 minutes on each side or until the fish is opaque and flakes easily with a fork.
Sprinkle the Cajun seasoning over the entire skillet and add the cream cheese. Stir until the cream cheese has melted and coated the mixture, creating a creamy sauce.
Add the cooked pasta to the skillet and toss everything together until the pasta is well coated with the sauce. If the mixture seems too thick, add a bit more stock or water to reach your desired consistency.
Remove the skillet from heat and stir in the minced cilantro. Serve hot, garnishing with additional cilantro if desired.