What are the three main types of fly fishing?

What are the three main types of fly fishing? The three main types of fly fishing are generally considered to be dry fly fishing, nymph fishing, and streamer fishing, based on type of fly and where in water column you fish. Dry fly fishing uses floating flies that imitate adult insects on water surface, most classic and visual, where fish rises to surface. Nymph fishing uses subsurface flies that imitate immature aquatic insects like nymphs and larvae below surface, most productive as most fish feed subsurface, includes indicator nymphing and Euro nymphing. Streamer fishing uses larger flies that imitate baitfish, leeches, or other prey, stripped through water to trigger aggressive strikes from larger fish. Some also categorize as dry fly, wet fly, and streamer, where wet fly includes nymphs and traditional wet flies. So three main types are dry fly, nymph, and streamer, covering surface, subsurface, and baitfish imitation techniques, each requiring different casting, presentation, and retrieve methods for different conditions and target species.