Weighty Considerations of Fly Design

Put your flies on a diet

Slim version of a callibaetis nymph

I had good reminder of a basic concept on fly selection last year when it comes to how fish will and won't take flies. I was fishing a high mountain lake with crystal clear water and was casting to a pod of very nice fish suspended about 6 feet down in 15 feet of water. They were actively feeding on Callibaetis nymphs, but not moving too much up or down. "Easy pickings", I'm thinking to myself as I slap on a proven nymph pattern and dropped it from my trusty indicator. Not only could I see the fish ignore my pattern, but they were also giving me the middle fin and laughing as I stood there in rejection.

However, as I continued to watch their behavior reacting to my fly, a couple of things became apparent. First off, they did not like the fly just hanging there in front of their faces as it tends to do whilst connected to a floating indicator. Secondly, while the fly did garner some attention from a few fish as it descended through the water column, I realized that the bead-head fly passed way too quickly through their "eating zone". I would get a bit of notice and movement from a curious fish, but the fly would continue to drop as I stripped it in and I would again be on the losing end.

Bead-Head Deep Dish Callibaetis

Once I realized the proper combination (i.e. non-stationary, yet not moving too quickly and in the "eating" zone), I tied on an unweighted nymph, ditched the indicator and watched the magic happen. The rest of the day was filled with successful sight fishing using slimmer unweighted callibaetis nymphs. The big takeaway though was just considering how my nymph selection skewed very heavily to the heavily weighted patterns. Time to retool the box and the tying approach.

So pulling from that lesson, there are a few things that I now make sure to incorporate into fly design when it comes to weighting or adding beads to patterns:

1. Consider the weight AND hydrodynamic (yes that's a big nerdy word) profile of a fly as it affects where in the water column a fly will travel. Remember weight will sink a fly but resistance from hair, hackle, dubbing etc will also affect the sink rate and the action in the water. One of the reasons I think the Cheech Leech, for example, is so effective is that it's not overly weighted with lead and other gizmo's and the copious amounts of marabou and dubbing help provide a bit of lift (and movement of course). To see what I mean, try throwing a Cheech Leech in a small shallow stream and see how it will literally glide through the water swimming more than it sinks.

Fall Cheech Leech

2. As you tie flies and consider the effect of #1 above, make sure you plan your boxes accordingly. In a nutshell, tie weighted and unweighted versions of your nymphs and even streamers. There will be times where you need the weight and times when you don't. Fishing a Copper John in a fast moving stream will really come in handy when you need the fly to descend quickly and get to or close to the bottom. On the other hand, as in my example above, you sometimes need an unweighted pattern that stays longer in the strike zone on its own. After this experience, I went back through my boxes and tied slimmed down versions of a lot of my nymphs -- especially stillwater patterns.

Unweighted slim version of a callibaetis nymph

3. Indicators are not always required and will sometimes be a hindrance. If you've done much Euro or Czech nymphing, you know that indicators of the floating variety can actually work against you in some cases when you want to have the fly control the sink rate and connect you more closely with the fish. So barring the presence of a flotation device and assuming a floating line, your fly will largely control how fast and how far it will sink. Sometimes a slimmer unweighted profile works better than a buggy weighted pattern -- especially in stillwater or slower runs or pools in rivers and streams. Then again, sometimes a heavy weighted pattern is what's needed. So taking the indicator out of the equation can sometimes help you better dial in your fly design and selection.

 At the end of the day, there are no hard and fast rules, but having similar fly patterns with varying sink rates in your arsenal will definitely be to your advantage. It sounds simple and logical to have both weighted and unweighted versions, but I'm slow on the up-take most days, so it's good to be reminded of this every now and again.