Demystifying the Types of Flies

Taking the Confusion Out of the Types of Flies

Central to fly fishing is the fly itself. The fly is an artificial representation of a natural food source that is used to lure the fish to bite the hook and are constructed of various materials that are tied onto a fish hook. There are literally thousands of different flies that can be used to fish the streams, lakes, and rivers of Colorado, but we will focus on the three main categories of flies used for trout: the dry fly, the nymph, and the streamer.

Dry Fly

Dry flies are designed to float upon the surface of the water and are made to resemble various bugs, such as stoneflies, mayflies, and even grasshoppers. The upside of a dry fly is that it is one of the more exciting ways to fly fish as you can see the fish rise up and take the bait. The downside is that this fly relies upon the fish coming up to the surface, which is not always the case, and that warm weather can drive fish deeper as they seek cooler water. Trout are also notorious for feeding below the water’s surface the vast majority of the time.


Nymphs are considered the most productive of the fly types used to fish for trout. The reason for this is that the nymph is designed to be used below the water’s surface and are designed to mimic immature insects that dwell underwater, who just happen to be a prime source of food for trout. The upside to using the nymph is that it is highly successful as trout feed most of the time (roughly 80%) under the water’s surface. There are a couple of downsides to using nymphs. The first is that the fly can become snagged on underwater debris. The second is that it takes some experience to detect when the fish bites as the angler cannot see the action. This drawback is often remedied by using a strike indicator so that the angler is aware of a fish taking the bait.


Streamers are artificial flies that mimic larger fish food types, such as leeches, minnows, and sculpins. The flies are cast out and then pulled, or stripped, in short or longer pulls. This movement of short or long bursts creates an illusion of a fly that is alive and moving. This pulsing style of movement is often irresistible to fish, making streamers the second most productive type of fly after the nymph. The downside to using streamers is that they are heavier, causing casting to be more difficult, and that the angler must be stripping the line to catch the interest of the fish. The upside to using streamers is that it is challenging, productive, and the results can be extremely dynamic as the fish explodes out of the water to take the bait.


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