What is a Fly Fishing Pupa and Tips For Using Pupae

Float like a butterfly, sting like a bee. This quote, often used in athletics, leaves out perhaps the most important aspect of these insects; their development. This is where fly fishing can take the reigns.

In the development stages, these insects are known as pupae and fish find them beyond delicious. There are numerous pupa fly patterns and all can be successful.

In scientific terms, pupae is the stage in development where complete metamorphosis occurs between the larval and adult stages. Larval structures such as cocoons break down during pupation and features like wings appear for the first time. Think of the transition between a caterpillar and butterfly.

What Do Pupae Flies Look Like?

First off, these flies are most commonly known as nymphs. For beginners, it’s best to group flies into categories and then as your knowledge grows, you can become more detailed.

Green Caddis Pupa
Green Caddis Pupa

The sizes of most pupae flies can range anywhere from 14 to 26 and are predominantly neutral looking with a small dash of color.

They are much shorter and thicker than larvae flies. Trout will often feast on pupae because of the time it takes for them to fully emerge as adults. Most pupae will float the water-column for miles before they find the proper conditions to hatch making them easy targets.

Pupae Flies will have a slight C shape to them. They will be wiggling while trying to hatch and in turn draw the attention of fish. Certain water calls for weighted or unweighted flies. It mostly depends on the speed of the current.

Beadheads, weighted nymphs, have a small brass bead near the islet that provides the necessary weight to reach the bottom. Non-beadheads are flies without weight that are meant to float closer to the surface.

We’ll get into more depth regarding what pupae flies to use later.

There are obviously thousands of types of pupae, but the most common are midge, caddis and mayfly. It’s important to know what types of flies are hatching in your area.

Midge flies look like mosquitoes, but they don’t bite. They often fly in swarms above the water.

Caddisflies look like miniature moths. Their wings have a tent-like shape and their antennae give the appearance of a moth.

Mayflies have extremely dainty wings and look like they have three small strings attached to their back. Golden mayflies are common and have a yellow body.

What is an Emerger Fly and How Does it Vary From a Pupae Fly?

When I see trout surfacing, the natural tendency is to throw on a dry fly. I’m often surprised how often this doesn’t work. As much as I want to see and hear my dry fly get slurped, I am often forced to tie on an emerger to get better results.

An emerger fly is one that is almost fully an adult, but not quite. They sit just below the surface and sometimes their wings will be above water.

There is a surface film on top of the water that fish utilize to their advantage when feeding. It also provides a space for emerging flies and pupae to fully transition into an adult. If fish are feeding on these, they will rarely even pay attention to the fly fully on the surface.

The main difference between emerger and pupae flies is the appearance. Emerger flies are almost fully developed. They have the wings and the tail, but aren’t quite developed enough to rise fully to the surface.

When Should I Fly Fish Pupae Flies?

Now let’s tackle the best times to fish a pupa fly. Since insects are developing year round, there is no specific month or time of year that pupae patterns must be fished. More emphasis should be put on time of day. By mid-morning, the flies should be transitioning from larvae to pupae and can be found in deeper water.

As the day progresses, the pupae will continue to rise and fish can be seen flashing just below the surface. They are feeding on the pupae that are beginning to shed their skin and nearly ready to break to the surface.

The two hours or so before dusk is a great time to fish pupae flies. They will be near the surface and fish will be getting ready for the evening hatch.

Favorite Pupae Flies

Choosing flies is always intimidating, regardless of skill level. Trout are extremely smart predators and are always going to be picky when it comes to what they eat.

As mentioned earlier, the best thing to do is observe what types of flies are in the area. Depending on where you are choosing to fly fish, do research on the bodies of water and see what is hatching.

In the next section, we’ll cover presentation of these pupae flies, so for now here’s a list of a few flies that I have found successful.

The first pattern is the caddis emerger pattern. It has a similar feel as a LaFontaine Sparkle Emerger. It has a size 16 hook and is predominantly tan and dark brown. It is a non-beadhead so it will sit nicely just below the surface.

The second is the green caddis pupa. There are many colors available in caddis pupa flies, but green has proven successful. Another name for it is the Green Sedge. These flies have a size 14 hook and are most useful in faster water. They mainly hatch from early spring to mid-summer. A great fly for mountain stream fishing!

bead head hares ear nymph
bead head hares ear nymph

A third successful pupae pattern is the Gold-Ribbed Hares Ear. This can be a good combination of a pupae and emerger. It represents a mayfly with its rabbit fur and gold coloring. While it won’t carry the weight to sink to the bottom, it leads to a lot of fun just before the flies fully hatch.

A fourth pupae fly that I enjoy is the Standard Brassie. I find myself fishing the Bighorn River in Wyoming and this fly always does the trick. There’s a thin copper wire tied around the hook and some peacock herl attached. It is a great midge representation and useful when tied behind a dry fly.

The fifth and final pupae pattern I’ll recommend is the Woolly Bugger. Most would classify this as a streamer, but I have found it to be one of the most versatile and successful flies around. It can be stripped and swung and everything in between. It’ll sit on the bottom and anger those bigger fish.

How to Present a Pupa Fly Fishing

Now comes the most difficult part of fly fishing: the presentation. There are a few simpler options to get started.

The first option is to tie a beadhead pupa on along with a strike indicator. This set-up will help you accomplish a dead drift. Throw the fly upstream and strip the line back to you. Mend the line a few times to keep the drift natural. Don’t be afraid to let the fly swing back around, it can often lead to some awesome strikes.

The second option is to tie on a non-beadhead pupae fly. The fish will likely hit these as they are rising to the surface. In order to accomplish this in a natural way, start by standing in the middle of the stream. Cast upstream to one bank or the other. Then, let the fly drift in front of you. Mend the line a few times upstream to keep the drift natural. Let the current handle the fly and as it passes, you it will start to swing. As it is swinging, grab the slack line and release it in short sections. It will create the upward wiggle we talked about earlier.

Final Tips

  1. An easy way to see what the fish want is to tie on a dry-dropper. More information on the dry-dropper can be found here.
  2. I would always recommend tying 2-3 feet of tippet to your leader to ensure the fly gets deep enough.
  3. Have fun. It’s a learning process! You’ll likely go through quite a bit of tippet when you’re first learning, but it’s as rewarding of an experience as there is.
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