Types of Flies
Flies or fly patterns (same thing!) come in a huge variety of styles, colors, and sizes for countless species. Flies can be specific imitations of various prey or simply "attractors" that try to provoke strikes with unique color or movement. Although many flies are more commonly referred to by their specific style or name, for simplicity's sake let's go over a few of the most general categories you should be familiar with:
While the term "dry fly" usually brings up images of a small insect-imitating trout fly, any fly that's made to float on the water's surface is technically a dry fly. These flies come in a huge number of sizes and styles from ultra-tiny insect imitations to massive creations made for saltwater fishing. A few examples of specific subcategories include attractors, terrestrials, and poppers.
A fly that's fished (you guessed it!) under the surface can be labeled a wet fly. Just like dry flies, various types of wet flies exist from old-school traditional patterns to nymphs and countless others! Speaking of nymphs, they are an extremely common type of wet fly—especially with trout anglers. Nymphs resemble immature insects and are popular for not just trout, but other freshwater species such as panfish, carp, and steelhead. Wet flies may often be weighted with things like lead wire, eyes, or bead-heads to help them sink even faster.
Designed to be fished under the surface, a streamer is another popular type of wet fly that can catch many fresh and saltwater species. Flies in this category often have long hair/fibers for increased action because they can imitate large, lively prey like small fish and leeches. A streamer is typically casted out then retrieved by stripping in the line which means the angler will likely feel the actual strike. The hits can be jolting and the rewards can often be big!