Fluorocarbon vs Mono: Which is the Best Leader Material

If you're wondering which is the better leader material, fluorocarbon vs mono, this article will go over benefits and drawbacks of each line type to see if there is a clear winner.

The Great Fishing Line Debate

Strike up a conversation about leader material and you'll quickly learn that anglers are prone to strong opinions, especially related to tackle. You'll also discover that while some opinions are based on factual evidence, others are based on experience, and most are based purely on good old-fashioned speculation.

Guesses and pondering aside, it's time to get to the bottom of the great debate: fluorocarbon vs mono and which is the best leader material.

First, let's take a look at what makes each leader material unique. Then, we'll compare the two side-by-side to see if we can draw a reasonable conclusion as to which is the better leader material.

First up we have the long-time standard, monofilament...

Facts About Monofilament

While we take monofilament fishing line for granted, it's a relatively new invention in the world of fishing, dating back to around 1938 with DuPont's invention of nylon.

Prior to monofilament, anglers relied on natural materials like silk, horsehair, and “cat-gut” — a material made from the fibers that line the inner wall of an animal's intestine, generally sheep or goat, not cat as the name would imply.

But before we digress into the history of fishing line, let's talk about nylon — the key component of monofilament fishing line.

Modern monofilament is made from a single strand of nylon material that has been melted down and extruded into the long, cylindrical shape that we know as fishing line.

Many different polymers and thermoplastics are used to make modern nylon monofilament fishing line. Most monofilament lines are treated and coated to make the line more abrasion and UV resistant, and are often pre-stretched to make them stronger.

Before we move onto fluorocarbon, it's important to note that when you see the word "monofilament" in relationship to fishing line, it almost always means "nylon-based." You'll see in a moment that without this distinction, things get confusing quick.

Facts About Fluorocarbon

Fluorocarbon fishing line is a type of monofilament fishing line made out of polyvinylidene fluoride, PVDF for short.

See what I mean? Confusing... Being a single-strand fishing line, fluorocarbon is technically monofilament. But no more technicalities; let's talk about fluorocarbon.

As a material, fluorocarbon was used for many other industrial applications before it was discovered to be an ideal material for fishing line.

The discovery was made in the late 1960s by a chemical engineer named Mr. Ishii of the Kureha company in Japan. Due to fluorocarbon's high-density and UV resistance, the material was being developed for use as a protective film for capacitors and to increase the UV resistance of exterior paint. When Mr. Ishii showed what he was working on to Mr. Yoshi, an angler working in the patent department of the company, they could see the potential to develop a new type of fishing line and quickly filed for a patent.

Long story short, the Kureha company released their new fluorocarbon fishing line under the name Seaguar, now a major player in the fishing line industry.

Talking about what makes fluorocarbon unique and different is difficult without comparing it to nylon-based monofilament, so let's get into the comparisons.

Both can be recycled.

Fluorocarbon vs Mono: How do They Compare?

Underwater Visibility

One of the most commonly spouted bits of info related to fishing lines is that fluorocarbon is nearly invisible in the water. Many anglers take this statement as fact, and while it is not entirely false, it needs some clarification.

Fluorocarbon is indeed less visible in the water than nylon-based monofilament. The refractive light index of fluorocarbon is more similar than that of monofilament to the refraction of water. But it is far from invisible, especially to the highly-tuned eyes of wary fish.

Often times, monofilament line comes in different colors other than clear to blend in with the color of the water to make it less visible. But when it comes down to it, your leader, whether mono or fluoro is visible to fish. Even so, if you want a slight advantage, use fluorocarbon.


When brand new and fresh-off-the-spool, monofilament has a higher overall breaking, tensile, and knot strength than fluorocarbon. But to get a real understanding of which line material is stronger, mono or fluorocarbon, you have to take other factors into consideration, primarily line elasticity and line density.

Line Elasticity

Monofilament line has greater elasticity than fluorocarbon. This means that when you stretch monofilament and release it, the line will retract or bounce back.

A high rate of elasticity is one of the main virtues of using monofilament as a leader — it acts as a shock absorber, making the line very strong.

It is generally believed that fluorocarbon does not stretch like monofilament does. The truth is, fluorocarbon does stretch, but it has less elasticity, meaning it doesn't bounce back.

Fluorocarbon's lack of elasticity is seen as a positive trait among anglers as it provides a more sensitive "feel" of the lure and the fish. But since fluorocarbon stretches without bouncing back, it becomes elongated and ultimately weaker.

Line Density

Fluorocarbon has a greater density than monofilament, resulting in a line that is harder, stiffer, and more abrasion resistant — three factors that contribute to the overall strength of a line.

Monofilament, being less dense, actually absorbs water and is more prone to surface damage that can weaken the line. So, while monofilament line has a greater strength when brand new, when you factor in wear and tear caused by fishing, fluorocarbon has a slight edge in maintaining its strength over time.

Another thing you often hear about fluorocarbon is that it sinks. This is true as fluorocarbon line is actually denser than water. This gives fluorocarbon the advantage over monofilament line when using subsurface techniques that require the line to sink quickly.

Being less dense, monofilament is typically preferred for topwater fishing applications as the line has near-neutral buoyancy and floats. However, since monofilament absorbs water, it will only remain floating on the surface for a limited time until it soaks up enough water and sinks.

Abrasion Resistance

One of the biggest advantages fluorocarbon has over monofilament is its higher level of abrasion resistance. Being denser, fluorocarbon can withstand more scratches, nicks, and dings while fishing than monofilament and still maintain its strength.

If you fish over coral reefs, shipwrecks, or stump-laiden reservoirs, using a fluorocarbon leader is the way to go.

Knot Tying Ability

Since fluorocarbon is denser and stiffer than monofilament, it is much more difficult to tie knots with.

When tying knots in your fluorocarbon leader rigs, extra care must be taken to ensure that each turn of the knot is situated perfectly. Gradually pulling the knot tight to get it seated properly is key, followed by a very firm pull to set the knot. Wetting the knot before tightening will reduce friction within the knot and will help it seat properly.

Monofilament, being more supple than fluoro, is the leader of choice for big game fishing, because even in very heavy sizes — 100-pound test and up — it can be knotted effectively.

In smaller line sizes, you won't notice much difference in knot tying ability between monofilament or fluorocarbon. But, if you're going after big game, monofilament is the way to go.

The Winner Is...

As you can see, there's a time and place for both monofilament and fluorocarbon. Monofilament is reliable, relatively cheap, and when used as a leader, gives you a nice shock absorber at the end of your line.

Fluorocarbon, being much denser than mono, sinks faster, gives you a better feel of your lure and has a higher level of abrasion resistance. But fluorocarbon is much more difficult to tie reliable knots in, especially in larger sizes, and it's quite a bit more expensive than mono.

So, for the average weekend warrior, the overall usefulness, thriftiness, and reliability of mono makes it our winner.  However, I'm sure the fluorocarbon vs mono debate will continue.

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