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Guest Blogger: Clay Cunningham, Cody WY, Former National Park Superintendent

Why would anyone want to pursue trout with an underwater fly when you can’t see it and know when a fish might have it in his mouth? Because 90% of the trout’s feeding habits are under the water where they select insects off the stream bottom and hang around in opportunistic locations to pick off dislodged insects that lost their grip on the stream bottom. Trout also become very active when pursuing insects making their way to the surface to dry off their wings and begin the process of reproduction.

No question about it, fishing nymphs or wet flies under the water requires experience and a sixth sense to know when a fish has your fly in his mouth. I have watched trout create a vacuum to suck in nymphs then expelled them with force in a split second if it didn’t suit them. How does one know when a trout surreptitiously pulls in one of your underwater offerings?

Well, when fishing nymphs or wet flies there are strike indicators that can be attached to your leader which gives you a slight hint that your underwater fly has either briefly hit the bottom or a fish has mouthed it. Or, you could fish with two flies. The upper floating fly would act as an indicator. Commercial bright colored strike indicators are highly visible because of their vibrant colors and it floats.  If it hesitates for the slightest split second; set the hook by lifting the rod. To tell the truth, I have only used an indicator once to test it on “educated” trout, but many nymph and wet fly fishermen use them with good success. Years ago I was fishing Spring Creek at Bellefonte in Pennsylvania. The water was as clear as glass and you could see the trout very well. I thought I would test the strike indicators. I am primarily a nymph and wet fly fisherman unless there is an obvious hatch of something. That experiment convinced me that the large aquatic inhabitants of Fisherman’s Paradise have a “PhD” in avoiding flies with a bright colored strike indicator floating along above the wet fly or nymph. That is not surprising as Paradise is one of the greatest fly fishing experiences in the east, and those fish have met up with the best fly fishermen in the world who travel there for the scenery and the challenge. Pennsylvania’s Paradise fish have seen the best fly fishermen.

At one point in my career, I was making daily law enforcement ski patrols hours before daylight each morning along the northern Yellowstone border when there was an extended elk hunting season in Montana. Before the legal hour to shoot an elk, many of Yellowstone’s elk were outside of the park boundary and could legally be shot if the legal time for such shooting was observed. Just before the legal time when one could shoot one of those elk, all the elk outside of the park border moved back inside the park boundary. These were experienced critters. Why should trout be any different – they aren’t. The elk learned from the experience of being shot at. So do the fish at Paradise, which is why so many of them survive to be large trout.

When I removed the strike indicator during the Paradise fishing experiment,  and made myself somewhat less visible with a low profile along the gin clear water while making quiet, minimal disturbing casts of my nymph far above of where I saw fish holding; I caught fish.

If you do not use a strike indicator you need to be able to read the water to know where fish are likely to be holding, and have good line management. This is what I do. I use a floating line that I keep well-dressed so it floats high. I attach a 7.5 foot leader to the line, and for fishing nymphs or wet flies I tie on an Orvis sinking leader to that leader. I’m not sure if Orvis still sells the braided sinking leader, but Rio Versileader does, and there may be others. My Orvis leaders are actually three leaders of different lengths and sink rates for different depths and the stream rate of flow. To the end of the braided sinking leader I tie on a short piece of fluorocarbon leader. Fluorocarbon is a smaller diameter for the same pound weight as the standard leader material. It becomes almost invisible in water. But, it also slips knots easily. When you use fluorocarbon to tie on your fly, use more windings for the improved clinch knot. With standard leader material you should wind the leader five times, but with fluorocarbon leader material wind it at least seven or more times before completing the knot. All my nymphs and wet flies are weighted. I tie those onto the end of fluorocarbon tippet with the improved clinch knot. To review, the 7.5 foot leader is attached to the fly line with a loop-to-loop knot, the sinking braided leader is attached to the level or tapered leader also with a loop-to-loop knot, as is the fluorocarbon leader attached to the braided sinking leader. Loop-to-loop knots are used because they are quick to tie on and replace or remove leaders.

With this rig you will soon learn from experience with the water’s velocity how far upstream you need to drop the fly for it to pass through the selected spot at the correct depth that you believe fish are holding. Keep your eyes on the tip of the floating fly line and if it makes any slight hesitation, set the hook easily by lifting the fly rod. If it doesn’t appear to hesitate, lift the fly rod to set the hook several times when you think your underwater fly is in the ideal spot you believe fish might be holding. You do not have to set the hook hard, because if it is in the mouth of a fish, the sharp hook will jag him and the fish will hook himself as it reacts to that jag. You will catch many fish right on the tip of their lip as it was trying to spit it out.


  1. So you’re recommending a “timed” hook-set, based on when the fly gets to where you want it…on the assumption that it’s likely to be in a fish’s mouth even if you don’t see or feel any twitch of the line. Interesting; I’ve always stayed with the “sensory” methods rather than just flat-out timing it.

    And I guess you can get away with that without spooking fish because you go real gentle on those hook sets.

    That strategy sounds powerful when you fully expect a fish to be holding there…and if there’s not one, it hasn’t cost you anything. I’ve hooked a fish or two over the years that I had no idea was mouthing my fly…just lucky timing. Your technique would tend to let an angler get “lucky” more often.

    Tell me…regarding those rigs you described for how you manage your fly depth…do you ever use little shot above the fly on the leader? What are your thoughts on using shot? I’m curious.

    Thanks for a thought-provoking article Clay,

    – Mike

    1. No, I never use split shot for extra weight I depend on reading the water, its rate of flow and adjusting the cast so my rig is at the right depth when passing through a suspected place I believe a fish could be holding.

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