How To Fly Fish Using Indicator Nymphing Techniques

Have you ever been on the water and wondered why the guy or gal fishing near you continually lands fish after fish? All the while your day is going relatively uneventful. You were hoping to have a fantastic day on the water. You took the day off work, loaded up on good flies, and arrived at the water early. Why is the other person doing so well? Are they using some hot fly pattern that’s irresistible to the trout? Are they in a better spot? What if I was to tell you it is probably neither of these things…

Nymphing is a relatively simple and very productive method of fly fishing once you understand 3 key things. Depth, weight, and drift are the largest contributing factors to a successful day on the water. Flies are a much smaller piece to the puzzle. Don’t get me wrong, effectively matching the hatch with size, profile, and pattern is crucial. But it does no good if the fly isn’t getting down to feeding fish and in a natural presentation. I have had many days on the water where others have approached me to see what flies I’m using only to discover they are using similar patterns. So what gives? The problem usually derives from the depth, weight, and drift or some combination of the three. If anyone of the three is off it will negatively impact your chances of landing fish. To better understand why these things are so important you must understand how a strike is detected.

A slice of paradise on the South Platte
A slice of paradise on the South Platte.

Using An Indicator

Success with indicator nymphing is being able to detect when a fish takes the fly. You won’t catch many fish if you can’t detect the strikes. A strike is detected by the tension created when the line goes tight. The fly stops, and the indicator continues to move downstream creating a tight line. Thus there is a delayed reaction of the strike until the line becomes tight. Adding weight gets the flies down to proper depth faster and helps to prevent your flies from traveling downstream of the indicator. If the flies are downstream of the indicator the reaction time for the strike is increased due to the increased distance the indicator has to travel to create a tight line. The fish will likely spit the fly before the strike is detected, resulting in a missed opportunity. Tension as well as slack between your weight and indicator are created by the amount of weight and depth you are fishing. Generally speaking your flies will move slower through the water the further your indicator is from the weight and faster when it is closer. You are trying to create a situation where your indicator and flies are moving through the water at relatively the same speed with the indicator further downstream than the flies. You don’t want your indicator pulling your flies through the water though! If the indicator pulls your flies through the water it will not appear natural to the fish. The flies should be drifting on their own with no pull from the indicator and thus a tiny amount of slack is the result, which is perfectly ok. Don’t forget the indicator should always be further downstream than the flies! If that is not the case then something is unbalanced. Adjusting depth, weight, and drift is how we achieve the fine balance.

Favorite spot to fish with my dad back in Idaho
Favorite spot to fly fish with my dad back in Idaho.

Set Your Depth

Generally speaking, place your indicator at 1.5 times the depth of water from your weights. In faster water I do 2 times the depth or more. You should continually fine tune for the water you are fishing. Weight and depth go hand in hand and there is a fine balance between the two. Neither are a constant. What I mean is there is no X amount of depth equals Y amount of weight. The water is far too great of a variable for constants to apply. I am always adjusting the depth of my indicator to continually fine tune. I recommend using Airlock indicators. They screw onto the leader and make adjustments quick and easy.

Add weight

It is difficult for flies to find feeding trout if there isn’t enough weight to get them there. Current pushes flies downstream as they sink. The faster the current the greater the distance flies travel before they get to the bottom. Weight reduces the distance flies travel before they get to the target depth. The weight also helps to adjust how fast the flies move through the water. Flies will eventually sink even without weight but it likely happen towards the end of the drift. Think about all that water you are drifting through where your flies are not at the target depth. Those are missed opportunities. I usually start with a #4 from Dinsmore Green Egg Tin Split Shot and add from there. I place my split shot 6 to 8 inches above my first fly (Note: A double surgeons knot in that vicinity will prevent the weights from sliding). I continually add weight until occasionally my indicator gets pulled under from the bottom early on during the drift. I then either keep my weight the same or remove a larger split shot for a slightly smaller one. Also casting farther upstream will give your flies more time to arrive at the proper depth. Remember no stretch of water is the same so it is best to continually fine tune your weight.

I love this view! I stop and enjoy the scenery every time I make the short hike in.
I love this view of the South Platte! I stop and enjoy the scenery every time I make the short hike in.

Drift your flies and don’t forget to mend

What is mending and why is it important for the drift? Mending is the action preventing drag. It is lifting and moving your fly line in a way that takes drag off of your indicator which in turn takes the drag off the flies. Not all sections across the water in a river, creek, or stream move at the same speed. There will naturally be sections of water that move faster than others. For an example think of a river where the current is faster in the middle and slower on the sides. In many cases not all of the fly line will be in the same speed of water. The indicator is moving in the faster water but the fly line has parts in the slower water. If you do nothing eventually the indicator will be pulled back from the slower moving fly line. The mend corrects this action by allowing the indicator to move freely through the current without being restricted by the fly line.

Indicator Nymphing Catches A Lot Of Fish

I hope this write up helped you to better understand how depth, weight, and drift affect your success on the water while indicator nymphing. If you take the time to adjust you will be amazed at how well you can do. Or you can just keep watching the other guy or gal find all the success on the water.

A fine example of a beautiful rainbow caught on my recent trip to the Gunnison river.
A fine example of a beautiful rainbow caught on my recent trip to the Gunnison river.

Written by Luke Petersen, fly fisherman and fly tyer

I am a Colorado fly fishing enthusiast from Colorado Springs. I spend my days on the beautiful rivers and nights on the tying bench. I can be reached on Instagram @luke_flyfishing

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3 thoughts on “How To Fly Fish Using Indicator Nymphing Techniques

  1. Luke is the son of one of my best friends in high school. He’s coming to join us for a few days of fishing and I look forward to watching him work his magic. I’ve been nymphing for 20 years and I still have a lot to learn but everything I’ve learned says that Luke is “spot on” with this article. Thanks for the reminders about the basics!

    1. You’re welcome and thank you for your comment Kevin! Yes, we loved his article as well and are proud to build a relationship with him!

    2. Thank you kevin!! It was a blast to fish with you while I was home. I think I’m gonna try to make it back for another trip this fall!!

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