Chenille is a popular material in fly tying for fly fishing due to its versatile texture and ease of use. Made from short fibers of yarn twisted around a core, chenille adds bulk and creates a lifelike appearance in artificial flies. It's often used to form the bodies of various fly patterns, including nymphs, streamers, and wet flies. Available in a wide range of colors and sizes, chenille can imitate the look of aquatic insects and other prey, making it a crucial component for creating effective, attractive fly patterns.