Streamer flies are a type of artificial fly used by anglers to imitate small fish, leeches, or other aquatic creatures. They are typically larger and more substantial than dry flies or nymphs, and are designed to be fished actively in the water column. Streamer flies are typically fished using a stripping retrieve, where the angler pulls the fly through the water in short, sharp movements. This action imitates the movement of fleeing baitfish and can trigger aggressive strikes from predatory fish.