Ask the Experts: How do you know when it’s time to change flies?

Guide Ivan Tarin of Salvelinus Fly Fishing selects a new pattern for me to try on a river in the western Pyrenees.
Photo by Sandy Hays

A couple years ago, we introduced a new weekly “Ask the Experts” Column and asked you to pose some questions for our panel of experts. Our latest question comes from reader Jerry Seitz, who asked: “How long should you stick with a fly if it’s not attracting any fish?” I’ve changed the wording to get at what I think is the heart of Jerry’s question.

I have never been much of a fly-changer, and I’ll often stick with the same pattern for a long time, unless I witness an actual refusal or don’t get a hit after working through an area where I know trout are holding. I once met an elderly gentleman on a river in Maine who told me that he’d whittled his entire fly collection down to three patterns: a Royal Wulff, a Hare’s Ear Nymph, and a Hornberg. He claimed that he didn’t see a drop-off in his success rate for trout and landlocked salmon. I believed him and have used that story for twenty-five years as motivation to become a better caster and angler. My theory is that the most common reasons that I don’t catch fish are that my presentation isn’t right, or the fish simply aren’t feeding. Fly selection comes in third on this list. So unless there’s an obvious hatch going on, I try to focus on finding the fish, casting well to put my fly in the right place, and then getting the proper drift or retrieve.

As you’ll see from our experts’ answers below, there are many different ways to look at the question, and opinions vary. If you’ve got a question you’d like to ask our panel, write it in the comments section below.

Brown Hobson, Brown Trout Fly Fishing (Asheville, North Carolina):
If fish density is high, I know fish are actively feeding, they are seeing my fly, and my drift is good, then I will only make three or four casts before changing flies. If the stream doesn’t have many fish, I don’t know where they are sitting, if I suspect they aren’t feeding super hard, or I’m having trouble getting a good drift, then I may leave it on for along time.

Some days, the fishing just isn’t good, and the best tactic is to leave your best two flies on and fish them as hard as you can. When fish are feeding hard, I find they will often take 20 different patterns that represent the bug du jour. For example, some days it doesn’t matter what color bead you have, whether the fly has a flash back, or exactly what shade of brown the fly is. Conversely when the fish aren’t feeding hard, they can be very picky and only a Pheasant Tail with a black bead, no flash, and chartreuse wire may work. I usually change often at first while I assess what my strategy should be. If all signs point to the fish feeding strong, then I keep changing till I’m popping fish regularly.

Capt. Lucas Bissett, Low Tide Fly Fishing Guide (Slidell, Louisiana):
In a saltwater situation where I’m sight-fishing, I let the fish decide if or when I change. If I see multiple fish react negatively to my fly, I change.

Kyle Wilkinson, Trouts Fly Fishing (Denver, Colorado):
My biggest rule for when it’s time to switch flies is when you begin to lose confidence in what you have tied on. It doesn’t matter if the fly you’re fishing is working for your fishing buddies, is what the local fly shop recommended, or what you read about on a fishing report. As soon as the confidence in your fly selection begins to fade, it’s time to switch. Sometimes that may be as simple as switching from a copper Copper John to a red Copper John. One Baetis pattern for another. Switching from a size 18 to a size 20. Etc etc. It doesn’t always have to be a drastic switch.

Capt. Dave Pecci, Obsession Charters (Charlotte Harbor, Florida):
Assuming you are making presentations where there are fish and not just blind-casting: I usually make 6 to 10 casts of varying retrieves, and then change up. It’s also a good idea to move off the fish to let them settle down and come back 20 to 30 minutes later. They may know you are there and develop lockjaw.

Tim Linehan, Linehan Outfitting Co. (Troy, Montana):
Determining when to change flies does not have to seem confusing or vague.  The better way to approach the subject is to ask yourself why your present fly might not be working. For the sake of simplicity, let’s assume you know you’re in productive water and that your drift is good, so that leaves us with an ineffective pattern as our only concern and how and when you might consider changing it.

  1. The first reason to consider changing your fly should be all about whether you want to concentrate efforts near or on the surface of the water or somewhere in the water column.  The old advice regarding dry fly fishing is to match the size, silhouette, and color of the naturals provided you’re seeing rising fish and natural insects are actively hatching, laying eggs, or otherwise animated on the surface. If there is no activity near the surface, consider changing flies and trying a nymph or streamer to penetrate the water column and concentrate efforts to that end.
  2. The second reason to consider changing your fly involves more specific themes.  If you’re still generally fishing near or on the surface, and you’re not catching fish but fish are rising and active, you have the wrong pattern. Consider changing flies frequently. It could be that you think fish are taking adults on the surface but they are really concentrating on swimming nymphs or emergers. By changing flies frequently you will increase your chances of hitting the jackpot more quickly.
  3. Finally, and this has always been my modus operandi, give a fly 10 minutes if you know you’re in productive water. If it doesn’t produce, change it. Be aggressive. You have all those boxes and all those patterns yoked around your neck and in your vest. Use them.

Capt. Tony Biski, Monomoy Fly Fishing (Harwichport, Massachusetts):
In saltwater, my general rule is to change flies only after you’ve tried every retrieve possible, to no avail.

If trout are attracted to your fly but won’t eat it, try going down in size.
Photos via

Joe Demalderis, Cross Current Guide Service (Milford, Pennsylvania):
The simple and short answer to this question is, when they’re not eating what you’re throwing. But in reality, there isn’t a simple answer. It would depend on whether we’re fishing dry flies, streamers, or nymphs/wets. I’ll start with dry flies because that’s where I think the answer becomes a little more obvious and easier to determine, though like all things in fly fishing, there isn’t an always nor a never–part of the beauty of it all.

With dry flies, personal observation has much to do with. And with dry flies, I’m referring to fishing to rising trout and not just blind casting riffles and seams. Try to determine what the fish is actually eating. Many times there’s more than one type of insect hatching, and the fish could be keyed in to that particular bug.

There’s usually more than one life stage present, too. Except for a pure spinner fall, you’ll have emergers, duns, cripples, and stillborn flies all drifting with the current. If you can see exactly what the fish is taking, like when a nose pokes up and sucks down a dun, bingo, problem solved. If you haven’t been fishing a dun, time to switch. Other times, the type of rise is what’s going to be indicative of what’s on the menu, so you would change flies accordingly. I’m not going to go into all of that here since I’d end up writing a book on that subject, and there are some good books that already cover that. One thing to keep in mind is to not worry about a fly change until you are 100% confident you have nailed the drift several times and did so while in sync with the fish’s rise pattern or tempo.

It’s funny how I’ve often heard anglers, and guides, claim that after after six fly changes they finally figured out the trout were only eating the duns that had one tail or whatever anomaly. What happened is they finally got the drift and the rise sequence in order; it just took ten casts with six different flies to put it all together. If you are confident in your fly selection, work on getting that same confidence in your presentation, adjust your casting angle if necessary. In other words, change your drift before you rush to change your fly.

With streamers, still try to match the hatch with a fly pattern that matches the predominant baitfish the trout have available. As long as you’re there, you might want to hold tight for awhile, too. Change up your retrieve: fast, slow, stop and go, whatever. There are times the fish aren’t in a chasing mood, and others when you want to rip a fly across their face to trigger that natural predatory instinct. When changing streamers, my first switch is usually size. There are days when they don’t feel like eating big and vice versa. Change streamers according to water conditions, too. In dirty water, I like a bulky fly that puts out some vibration that the trout can home in on with their lateral line and not just depend on vision. I want a color that’s going to give a good silhouette from the fish’s point of view too.

I generally don’t change nymphs too frequently, except to deal with the water conditions at hand. After selecting my fly based on what’s been the most active hatch (always back to the “match the hatch” scenario), I’ll make changes as the depth and speed of the water change, and also the habitat that various insects are most likely to be found in. This comes down to fly weight, size, and type. Here again, concentrate on presentation, and you’ll find yourself being successful without having to tie so many knots and using up yards of tippet.

In the end, the fly pattern you have the most confidence in, that you keep in or on the water the most, will catch the most fish. Change your fly when your gut tells you too. It will renew your confidence and focus, and you need both to be successful. A fly change also gives you time to chill for a bit and regain your composure. It gives the fish a break from incessant flailing and helps it to settle down again to a comfortable feeding pattern. Ever notice how a fish seems to start rising better while you’re retying a fly?

Capt. Chuck Hawkins, Hawkins Outfitters (Traverse City, Michigan):
I change my pattern frequently if I’m not getting results, especially after a refusal to a dry fly from a feeding fish. A follow on a streamer doesn’t count as a refusal, though. If I’m getting looks on a streamer, I’ll stick with it a while or make slight change in size.

If at any point, I’ve lost confidence in the bug, it’s gone. Fired and back to the box!

Maggie Mae Stone, The Tackle Shop Outfitters (Ennis, Montana):
Changing your flies can be the contributing factor to having a stellar day on the water. I will typically swap out after 30 to 40 minutes of inactivity.  Before I change, however, I also adjust split shot and leader/tippet length, as they can also make a huge difference, depending on current speed and water depth.

When it comes to dry flies, and fish are hitting the surface, it becomes pretty obvious if your fly is working or not based on the strikes or lack thereof. Sometimes “matching the hatch” just isn’t enough, and you have to be creative with your selection. I can think of a million times where caddisflies are blanketing the water and you would think you could throw on any typical caddis pattern. But instead, that size 18 Spruce Moth might work better! Keeping a wide variety of flies and different hook sizes is a good idea.

Another good thing to remember is that aquatic bugs may be moving around more depending on the time of day. Sometimes a certain fly will work great in the morning, and not at all during the afternoon. I notice this on my float trips as well. Certain sections of the river have more bug activity than others it seems. My number one fly that I throw on when nothing is working would be the Lightning Bug, which produces fish almost any time of year. When in doubt, change it out!

Kip Vieth, Wildwood Float Trips (Monticello, Minnesota):
As guides, we often fall into a rut of riding a particular pattern longer than we should. They have worked for us over the years, and it is our comfort zone. Stepping out of that can often times be tough, but if you’re simply not moving fish it’s time to change.  As you spend more time on the water, you will get a feel of what is going on. Use your gut instead of your heart, and I think it will go a long way in helping you make that decision.

Doc Thompson, High Country Anglers (Ute Park, New Mexico):
This is an often-asked question on guide trips. There are many factors to consider, from water conditions to skill level. If conditions, fly presentation, drift, etc are at least decent, here are a few guidelines that should be helpful.

  • When blind-casting for trout, try changing flies when you have covered a few prime holding spots and/or feeding lanes thoroughly with good casts and drifts.
  • When sight-casting to trout, try changing fly every 2 to 3 fish if you aren’t getting any looks or takes with good presentations and drifts.
  • If trout are attracted to but refusing the fly, it usually means you’re close to the right fly, so change to a smaller fly.  If changing to a smaller fly doesn’t help, try dropping down a size in tippet or a similar fly tied in a different style.

Rob Woodruff, Woodruff Guide Service (Quitman, Texas):
Anglers tend to “blame the fly first” and change patterns when things are slow and not look at other possible factors. Before I change flies I do two things:

  • Check the leader and tippet for tangles knots, kinks, etc. that the fish may be seeing or that may be affecting the quality of the presentation.
  • Analyze the quality of the presentation. For dry flies and nymphs, is the fly being presented in a drag-free manner? In the case of nymphs and streamers, does it need to be deeper?  For streamers, I try changing up the retrieve for a few more casts.

If the leader and tippet are good and we have made at least a dozen proper presentations in a spot that usually holds fish, then I change flies. My philosophy for bass, trout, and saltwater is to go to smaller flies when things aren’t working.

4 thoughts on “Ask the Experts: How do you know when it’s time to change flies?”

  1. Do you have any preferred methods for carrying big streamers to and from the water without them getting rusty and ruined?

  2. I really enjoyed reading ,what all the trout fishermen had to offer “when to change a fly”. I live on a very small lake,which is home to small.lg. Mouth,crappie,bream,and blue gill.I recently started tying my own.I go with one pattern,which I claim to have invented ,and one day I caught one of each of the above on that same lure.I don’t always catch a fish,but only spend 10 to15 min.s. A day.(I return them to the water)I am 85 yrs. Bob A .

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