Every angler has their favorite knots. But the longer we fish, the more we encounter situations where what we usually do just doesn’t work. So we learn from it. We research and we ask other anglers. And maybe we find a rig, a tactic or a knot that solves the problem.
That’s part of what we love about this fly fishing game. It’s a never ending set of new circumstances and new mysteries with new solutions.
Let’s consider the Uni-Knot. Because this one knot can do many different things. It solves problems and opens up opportunities.
In the video below, I show the following uses for the Uni- Knot
- Tie on a fly (standard or as a loop knot)
- Attach flies as a trailer, and then back them off
- Create tags for droppers
- Connect two lines (Double Uni-Knot)
- Attach line to a reel spool
- Attach leader to fly line (through the loop or as a Nailless Nail Knot)
- As a stopper knot (for slidable dry dropper rig or as a bobber stopper)
- As a sighter while fishing nymphs or streamers
Watch the following video, and then scroll below for more details about the many uses for the Uni-Knot.
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Why the Uni-Knot?
The Uni-Knot is universal — one knot to rule them all. Because, with just the Uni, you can do everything needed on the water — literally everything. The Uni-Knot does it all. So if you want to simplify your knot selection, this is your knot.
Incidentally, a few other knots seem to steal from the Uni-Knot and rename it. For example, the Duncan Loop is a Uni-Knot that isn’t fully closed. The Grinner Knot is also a Uni-Knot.
Ways to Use the Uni-Knot
Attach a Fly
This one is simple . . . with an option. I choose the Uni when the wire diameter of the hook eye is large enough that my favorite Davy Knot might slip. Instead of a Double Davy, I choose the Uni. I rarely use a Clinch anymore, instead choosing the Uni-Knot.
What’s the option? If you don’t tighten the Uni all the way, you create a loop knot. (Again, the Duncan Loop.) This is a slidable loop knot that usually cinches down while fighting a fish. If the tippet and hook diameter is large enough, you can easily back the knot out again to create the loop after it closes. In truth, I rarely use the loop feature of the Uni and instead choose the Non-Slip Mono Loop.
However, I do like the back-off feature of the Uni-Knot for the following application.

Photo by Josh Darling
Attach a Trailer
Multi-fly rigs can be created in a host of interesting ways. I usually run tags, but I sometimes choose trailers.
READ: Troutbitten | Tags and Trailers
Using a Uni-Knot for the trailer allows me to loosen the knot to remove the trailer and the attached tippet. Store that away for later and attach it again when needed.
It’s a great feature.
Create a Tag
As mentioned, my favorite way to run a multi-fly rig is with a tag. There are a few ways to create tags as well. Here’s a dedicated video on the topic:
VIDEO: Troutbitten | Three Great Ways to Create Tag Droppers
I use the Uni-Knot for what I call the Add On Line method. Tie it around the mainline, snug it up, slide it down to the mainline knot, and tighten it. Done.
READ: Troutbitten | The Add On Line
Connect Two Lines
Splicing two lines together can be tricky. Fly anglers tend to use two standard options: the Double Surgeon’s Knot or the Blood Knot. Both are great solutions, with their own drawbacks.
Another option is the Double Uni Knot. It has the slim, clean profile of a blood knot, while it also has the advantage of joining almost any two lines together, regardless of how different the diameters are.
I use the Double Uni-Knot most when joining braided line to nylon or fluoro. But it’s a great option anytime two lines must be spliced together.
Line to Spool
If you attach your own backing to the reel (you probably should), you need a solid knot. The Uni-Knot works on any reel, with any type of line, from spinning reels and braided line to fly reels and twenty pound backing.
Forget the Arbor Knot. The Uni-Knot is stronger and simpler.

Photo by Josh Darling
Leader to Fly Line
I change leaders often because I make it easy. It still surprises me how many anglers handicap themselves because they see the fly line to leader junction as almost permanent. Loop to loop connections are a poor choice too. Keep things simple so you can change leaders quickly. I’ve been through this before . . .
READ: Troutbitten | Loop to Loop is Bad — Attach Leaders This Way
VIDEO: Troutbitten | Lighting Fast Leader Changes
I use the Uni-Knot here in two different ways:
First, attach the leader by tying it to the loop of the fly line — treating it like a hook eye. I usually use a Clinch Knot for this. But if it slips (often when the leader butt diameter is thin) I employ the good old Uni-Knot.
Second, if the fly line does not have a loop, then a Nail Knot or a Needle Nail Knot are my favorite choices — but not on the river. For a down and dirty, quick way to attach the leader to a fly line, I use a simple Uni-Knot, as shown in the video above. This is very close to a Nailless Nail Knot, but I can do it more reliably.
Stopper Knot
The Uni-Knot makes a great slidable stopper knot on any leader or tippet diameter. Stopper knots are useful in a slidable dry dropper setup, and as a bobber stopper.
READ: Troutbitten | A Slidable Dry Dropper System
These stopper knots can be tied from mono or from a braided material like Dacron.
Backing Barrel Sighter
For many years, I’ve spread the word about a unique and versatile sighter that attaches anywhere on your leader or tippet. I call it the Backing Barrel, and it is formed with a Uni-Knot and a short length of hi-vis Dacron backing.
READ: Troutbitten | The Backing Barrel May Be the Best Sighter Ever
Clipped flush and used as a barrel only, or with a one-inch tag dangling, the Backing Barrel Sighter provides an amazing reference for many underwater fishing scenarios (nymphs, streamers and wet flies).
Often, Not Always
The video above shows the standard Uni-Knot in great detail. Remember, all of these uses are just the Uni applied in different ways. Learn the basic Uni-Knot. Then adapt it to the situation.
I’m sure there are even more uses for the Uni-Knot. What I’ve shown here are the ways that I use it every day on the water.
If you have another way to use the Uni, please leave it in the comments sections below. That helps everyone.
One final point, here. I don’t use the Uni for everything. Because sometimes there are better knots that suit the application. But remember, the Uni Knot is always there, waiting to solve your problems.
Fish hard, friends.
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Enjoy the day.
Domenick Swentosky
T R O U T B I T T E N
domenick@troutbitten.com
Dom
If you use a uni knot to add on a dropper above a main knot I saw you cut the top tag..can you use the top tag, similar to an Orvis knot, or will it be weaker when fighting a fish?
Good question. No, you can’t use the up tag. It breaks too easily.
Hey thanks for this. I HATE nail knots. I don’t tie them often any more because of welded loops but I do use them on your night sighter. After watching the video I may never need to tie one again.
Your grass is looking great. Strong yard game player!
Ha. Thanks. Good rain this year
Hi Dom great video and article thank you. Just wondering what’s your preference for tippet to fly connection ( fresh water ) Davy Knot or Uni Knot. I recall the Davy was once your favourite, has your preference change if so can you explain why please.
No, it hasn’t changed. As I said in the video and article, I don’t use the Uni all the time for all these applications, but it’s always there as another option. Sometimes it’s the best option. I still prefer the Davy most of the time.
As always, awesome stuff. Nice to have that Uni when you need it.
Thank you
Uni-Knot is ideal for backing to fly line. Why manufacturers add a welded loop to the running line (reel end) is mystifying. Just cut it off and attach backing with a 4 or 5 turn Uni.
Oh, I much prefer the welded loop, honestly. I just clinch knot or uni knot my leader to that loop. Easier, faster and doesn’t eat up any fly line. When you change leaders a lot, that’s important.
I wasn’t referring to the welded loop on the leader end. It’s the welded loop on the reel end of the running line to which the backing is spliced. Sure, you can attach to that loop with a clinch or Davy, but I prefer a Uni as it’s a cleaner knot and it’s not unusual for Delaware rainbows to quickly get you into the backing.
Good stuff
Domenick:
I’m interested in purchasing one of Troutbitten’s “Full Mono Rig Kit’s” which are currently out of stock. I would appreciate a heads up once you have replenished this item back into your inventory.
Thanks,
Hi John,
The next sale is planned for November. Please subscribe to Troutbitten (it’s free). You’ll then receive notifications for all new articles. There will be an article announcing the November sale.
Thank you.
Dom