Place a large pot of water over high heat for the pasta. When the water is boiling, salt it and drop the pasta. Cook to al dente according to package directions. When the pasta is ready, drain it and reserve.
As soon as the pasta goes into the water, place the butter and garlic into a small pot over low heat and cook until the pasta is ready.
While the pasta is cooking, season the shrimp with Old Bay, fennel seeds, salt and pepper, and reserve.