Understanding Flies: Dry Flies, Nymphs, and Streamers
The "flies" in fly fishing are artificial imitations of the creatures fish eat. They're tied from thread, feathers, fur, and synthetic materials onto small hooks. There are thousands of fly patterns, but they all fall into three main categories:
Dry Flies (Surface)
Dry flies float on the surface and imitate adult insects — mayflies, caddisflies, stoneflies, grasshoppers, and others that sit on top of the water. Fishing a dry fly is the most visual form of fly fishing: you can see your fly, see the fish rise, and see the take. It's electric. Good starter patterns include the Elk Hair Caddis, Parachute Adams, and Stimulator.
Nymphs (Subsurface)
Nymphs imitate the immature, underwater forms of aquatic insects. Fish feed below the surface far more often than on top — some estimates put it at 80-90% of their feeding. Nymph fishing is less visual but extremely effective. Starter patterns include the Pheasant Tail Nymph, Hare's Ear, and Copper John.
Streamers (Baitfish Imitations)
Streamers are larger flies that imitate minnows, crayfish, leeches, and other bigger prey. You cast them and strip (pull) them back through the water to create movement. Streamer fishing often produces the biggest fish because larger trout and bass are more likely to chase a substantial meal. The Woolly Bugger is the single best beginner streamer — and arguably the most versatile fly pattern ever invented.
Sensei's Note
When in doubt, tie on a Woolly Bugger. It imitates almost everything — a leech, a minnow, a crayfish, a dragonfly nymph. It works in rivers, lakes, ponds, and salt. It catches trout, bass, panfish, and just about anything else that swims. If I could only fish one fly for the rest of my life, it would be a size 8 black Woolly Bugger.
You don't need to understand entomology to start catching fish. A small assortment of proven patterns in a few sizes will cover most situations. Your local fly shop is the best resource for what's working on the waters near you.