Dry Flies or Nymphs Basic Steps for Identifying a Hatch

The goal in this article is not to get into the age-old debate about which method is the best or the most “pure”. In my opinion, both dry fly (flies that imitate insects on the surface) and wet flies (sometimes called ‘nymphs’, these patterns imitate sub-surface food sources) each have a distinct place when trying to be as productive an angler as possible. There are circumstances where a preferred method of fly fishing is developed over time, and the bottom-line is to concentrate on what you find the most enjoyable way to fly fish for trout. That said, to be a complete, year-round fly fisherman, you will need to utilize both techniques in order to stay on fish all day.

Once you gain some confidence in fly casting and you get to the river, where do you start? First, you have to get set up properly, and I will go over these steps in another article. When you get to the water and start the fly selection process, what is the next step? First of all, you should observe the water and ask yourself three simple questions:

1. What type of water am I about to fish? Is it nymph water or dry fly water – or both?

2. Can I see fish feeding? Pay attention to whether the trout are feeding on the surface, in the surface-film, or “flashing” near the bottom.

3. Do I seeany insects flying around, especially near the surface of the stream?

Question number one deserves its own topic, so let’s start with question two. Let’s face it, most of the time on the trout stream you will not see fish at all, whether the trout are feeding or not (of course there are notable exceptions to this). If you are at the right place at the right time, the fish will tell you what to do, but never count on that being the case. In general, if you aren’t seeing rises on or near the surface, it’s time for a deep presentation with a sub-surface pattern. If you see flashes near the bottom, the trout are feeding on nymphs. Knowing the entomology of a certain stream will help in deciding what nymphs to use. For example, if you know that some caddis have been hatching, or you see some caddis flying around -and the fish are not feeding on the surface – it would be a good time to try a caddis nymph. I will cover this subject in far greater depth at another point in time, and I will describe simple, “confidence” flies that can imitate a wide range of in-stream foods.

When you see insects on the water and fish feeding, you are in a great position, because it means that it will be a relatively easy process to figure out what the fish are feeding on (unless the bugs hatching are miniscule), and dry flies will probably work better than nymphs. Pay attention to which bugs the trout are keying in on. To oversimplify this process, caddis will appear “moth-like” with a big wing. They dive bomb the surface when laying eggs, and often caddis get trapped fluttering on the surface. The most common caddis colors are: olive, brown, tan, and gray. A caddis hatch is easily imitated and big fish can become aggressive during this hatch. Mayflies, on the other hand, are beautiful insect specimens that often float down the river in droves, but they can be more difficult to identify. Most mayflies have a pronged tail, an extended body, and wings that look like a little, rounded sailboat sail. There is much mysticism surrounding mayfly hatches, perhaps because trout are often picky when mayflies are on the water. On the other hand, trout will usually throw caution to the wind during a caddis emergence. A few good mayfly colors to start with would be: yellow, gray, green, and brown. There are wide ranges of beautifully tied, extended-body mayfly patterns available. In future articles, I will discuss a few simple mayfly options that catch big fish.

Hopefully this will help those new to fly fishing. Books and fly fishing videos have been written and produced on nymph and dry fly fishing, but I find it best to simplify the process whenever possible. This is especially true when learning the sport. There are multitudes of other hatches besides caddis and mayflies, but these are the two most basic ones. It always pays to research specific hatches and subsurface food sources before heading to a new piece of water. Most local fly shops are very helpful, so don’t be afraid to call one and ask questions…this is what they are there for. You can also drop me an email if you want to discuss this topic in greater depth.