Cook pasta according to package directions, omitting fat and salt. Drain pasta over a bowl, reserving 3/4 cup pasta cooking liquid for the sauce.
Heat oil in a large skillet over medium. Add fennel; sauté 7 minutes. Add crushed red pepper, salt, and garlic; cook 1 minute. Add crab; cook 2 minutes, stirring occasionally. Add pasta and reserved 3/4 cup pasta cooking liquid; toss to coat. Stir in 3 tablespoons parsley.
Divide pasta mixture among 4 bowls; top evenly with remaining 2 tablespoons parsley, basil, and mint. Serve with lemon wedges.
Adapted from Back Pocket Pasta: Inspired Dinners to Cook on the Fly, by Colu Henry