Ah, the classic debate, which is better Nylon or Fluorocarbon? While much of this is up to debate based on opinions, here is a more scientific breakdown of the difference between monofilament and fluorocarbon that will help you understand each material’s strengths and weaknesses.

What is Monofilament (Mono)?

As its name implies, monofilament fishing line is a single strand of material extruded from nylon. Depending on the brand, different varieties of nylon are often blended together to produce varying degrees of stretch, strength, abrasion resistance, density and other attributes.


Due to its flexible, supple nature, mono is easy to work with, which makes it especially more manageable to cast than stiffer lines.


Most mono stretches more easily than fluorocarbon which can be advantageous when fighting a fish. A downside of stretch is that more stretch means less sensitivity.

Sink Rate/Density:

Mono is generally a larger diameter which is directly linked to a slower sink rate. The slow sink rate, coupled with its near-neutral buoyancy, makes mono a great choice for dry fly fishing or suspended subsurface presentations.


Mono has a lower tensile strength than fluorocarbon which means that it has a thicker diameter at a given break strength. Additionally, mono is permeable to water and slowly absorbs water throughout the day, causing it to weaken. Over the long term, mono is also susceptible to conditions like U.V. rays, rain and humidity, and extreme temperatures.


While many companies create monofilament with different tints and colors to make it more invisible to the fish, most monofilament, especially in brighter conditions, tends to make fish visually aware of its presence.*


Due to its great handling, mono has superior knotability compared to fluorocarbon. For this reason, mono is also the preferred choice for big game fishing because it allows big diameter lines to seat better to avoid knot slippage or breakage.


Monofilament is one of the most affordable of all line choices and is relatively inexpensive in comparison to fluorocarbon. You can pick up some of your own, here

Best Applications:

Dry fly fishing, wet fly fishing, emerger fishing, fishing that requires large diameters.

What is Fluorocarbon (Fluoro)?

Fluorocarbon is a family of synthetics and compounds including fluorine, chlorine, and carbon that is extruded into a single strand similar to monofilament. However, because fluorocarbon’s molecules are more tightly packed, the line is denser and has better tensile strength than mono.


Harder, less supple, and thus more difficult to handle than mono. Fluoro is more prone to line memory.


Due to its tightly packed molecules, while fluoro has less stretch, it transmits more energy than mono which gives you much more sensitivity. The lack of stretch allows better telegraphing of information from the end of the line to your rod tip, such as subtle bites or being able to feel your fly ticking along the bottom.

Sink Rate/Density:

Fluorocarbon is tightly packed and therefore much more dense than mono. This density allows it to sink much faster, even at smaller diameters.


In short, fluoro is a much heartier material that results in higher abrasion resistance that is useful in situations such as tight line nymphing or fishing heavy cover. Unlike mono, fluoro does not absorb water throughout the day and is extremely resistant to the various conditions mentioned before which makes it a much more reliable line for constant, all-day use.


The light refractive index of fluoro is very similar to that of freshwater, which means that it is much less visible in water than mono. Additionally, the high tensile strength allows you to use smaller diameters with high strength and still maintain low visibility.


Fluoro’s stiffness does not lend itself well to knots. Particularly with larger diameters, knots do not seat well which often causes slippage or breakage.


One of the greatest downsides to Fluoro by far is its price. Often you will see 30yd spools of tippet going for almost $30 dollars, but sometimes its benefits outweigh its high price point. Pick up some of your own, here.

Best Applications:

Nymphing, fishing around heavy cover, anything where you need the extra sink factor and abrasion resistance.

So, there you have it. Each line has its own advantages and disadvantages and hopefully, this breakdown will help you buy the right line type. Be cognizant though, there are many variations even within line types depending on the manufacturer.

The article was written by Matteo Moretti.

*Based on results from this scientific paper.

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  1. […] We were throwing 5 and 6 weight rods on floating lines with 3 X tippet. Luckily with the size of these bugs, you can get away with a heavier leader, no need for 5 and 6 x here. When it comes down to choosing the right rod to fish the hatch I would recommend a good 6 weight rod with a 6 or 7 weight line. It helps when throwing big bugs and if you hook into a proper trout you want to be able to land it as quick as possible. Read our guide on choosing the right tippet. […]

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