What is A Nymph and Dry Fly?

Every once in a while it is good to cover some basics with terminology and tackle. For most that are curious about fly fishing they usually have the image of a dry fly floating on top of a stream. Maybe they've seen a YouTube video or have driven by someone fly fishing. When they come fish with me in the Shenandoah Valley I usually get some kind of over-animated arm waving that is their idea of casting. Hey, we all have to start somewhere...

Dry fly fishing is amazing but not usually the norm when it comes to fly fishing year round. Most of the time we are using nymphs that are underwater and not visible when you are fishing. Nymphs represent the immature stage of the macroinvertibrates (little bugs) that live under the rocks in the stream bed. These little bugs are what trout eat year round and ninety percent of the time the eat them below the surface of the water. It is only that rare perfect weather day that these immature bugs grow up and turn into adults, mate, and then come to lay their eggs. It is during this event, or hatch, that the trout feed on the surface and you see the image that most people think of. Swarms of insects, ripples on the surface, and trout feeding on an enormous amount of food.

This is the time that we use dry flies. These flies are intended to float on the surface and we apply fly floatant, which is a water repellent, to help. They are still made of fur and feathers so eventually they get wet and will start to sink and we have to change them out. Also that particular insect will only be in that adult stage for one day and hatches are only a few consecutive days out of the year so the right size and color are very important.

One other term I am going to throw in as you might encounter it is a fly we call an emerger. It is kind of in between a dry fly and nymph. This fly is supposed to mimic the stage where the immature bug is becoming mature. Mayflies in particular float up to the top of the stream and get wings, then are able to fly off. At this time they are very vulnerable as they get caught in the surface film of the water. Fish see these bugs coming up from the bottom of the stream, or "emerging". These flies do not float on the surface of the water, but slightly below as to resemble these bugs coming upward. As a beginner I wouldn't recommend fishing with these, but just in case you have heard of them and were curious.

Just remember, if fish are eating below the surface the vast majority of the time, that is where you should be fishing. Those big, puffy dry flies look great in the shop, but fill your box with more nymphs than dries and put it where the fish are eating for more success.