Nylon monofilament, braid, and fluorocarbon are all valid fishing line choices for your fishing reel. But each one behaves differently, and depending on the situation, you may opt to choose one over another.
What are the actual differences between monofilament, braid, and fluorocarbon fishing line?
Everybody who has been fishing at least once in their lives has probably used monofilament fishing line. It is the most widely available, the most affordable, and the easiest to work with for most anglers. Many retail fishing rod and reel combos come from the factory wound with monofilament. It's by far the most popular choice, and it has caught millions of anglers billions of fish over the years. But for some reason, monofilament has been tagged with an unfair reputation as something only a beginner (or a bad angler) would use. That isn't necessarily the case.
Fluorocarbon line is a lot like monofilament. It has similar diameter, similar abrasion resistance, and is often sold alongside monofilament in bait and tackle shops. Fluorocarbon is usually only sold in a clear color, usually at twice (or more) the cost of equivalent diameter monofilament.
Braided line is very thin for its break strength and is rope-like in its construction. It consists of four or more separate strands of material braided together, which is what makes it so strong for its diameter. Per foot, it is often the most expensive option of the three due to its production cost. You'll usually see braided line on baitcasting reels and conventional fishing reels, and not so much on spinning reels.
But there are a lot of factors that go into answering the question, "What fishing line should I use?"
Monofilament stretches more than fluorocarbon.
This is one of the biggest distinctions between them. And it's not so much about stretch, but what happens after the stretch.
When you catch a fish (or a snag) on a rod and reel wound with monofilament, you will experience a little bit of line stretch when setting the hook or tugging against your snag. On one hand, this can sometimes prevent a good hook set on a fish, and this is one of the reasons why a lot of anglers discourage the use of monofilament. While this is entirely possible, that stretch will also provide a margin of error before the line snaps. This can be desirable in some situations, like when you are trying to get your rig back from that submerged log or rock pile, or when setting the hook on a fish that is testing the limits of your line. Generally speaking, monofilament will stretch and then return to its original length.
Recent research has discovered that fluorocarbon line will also stretch, but the real difference is that once it stretches, it does not return to its original length. One a length of fluorocarbon line has been stretched to its limit, it stays deformed, and will often lose strength as a result. The lack of a return, or lack of elasticity, is probably why most anglers perceive fluorocarbon to not have any stretch. This also manifests itself as "better feel" or "more responsiveness."
This is also what causes fluorocarbon to be perceived as stiff or brittle. While monofilament will sometimes stretch and spring back, fluorocarbon will stretch and not spring back. If this happens enough, fluorocarbon loses its strength. When the line becomes damaged, this stiffness will weaken your line almost entirely.
What about braid? Well, the amount that braided line stretches is so little in comparison to monofilament and fluorocarbon that it's not even worth considering. This is why most anglers will tell you that "braided line does not stretch."
Braided fishing line has a high tensile strength for its diameter.
Imagine you have braid, monofilament, and fluorocarbon line, all the same diameter. The braided fishing line will be the strongest of the three, and the monofilament fluorocarbon will be nearly the same strength as each other. Fluorocarbon and monofilament line are so close in strength and diameter that they are functionally identical. Differences in diameter between the two at a certain weight test are measured in 1-2 thousandths of an inch. This is so insignificant that they can't be seen or felt by an angler. Anybody who tells you that fluorocarbon is considerably thinner than monofilament is misinformed, or they are trying to sell you expensive fluorocarbon line.
But pure weight test is not the only measure of line strength.
Braid has very little abrasion resistance compared to monofilament or fluorocarbon fishing line.
While braid may be the champion of break strength vs. diameter, it's also the weakest of the three in terms of abrasion resistance. This means that a braided line rubbing against a rock, wood piling, or other sharp objects will break before equivalent diameter monofilament or fluorocarbon line. This is why you will often see braid used as a mainline with either monofilament or fluorocarbon as a leader.
There has been a debate about whether fluorocarbon or monofilament has better abrasion resistance. The conventional theory is that fluorocarbon has more abrasion resistance than monofilament, but recent tests have shown that this isn't necessarily the case, and both fluorocarbon and monofilament have very similar abrasion resistance profiles. So when choosing between the two, abrasion resistance should not be your first consideration. Instead, consider the other characteristics of the two.
Clear fluorocarbon is harder to see in water than monofilament.
Old conventional wisdom was that fluorocarbon line was invisible underwater. Independent testing has refuted this, and both fluorocarbon and monofilament are somewhat visible underwater by human eyes. But fluorocarbon refracts slightly less light than monofilament, making it slightly harder to see underwater. Clear monofilament won't be invisible, but it can come close. Braided line usually isn't clear, and if you do find clear braid, it will be very visible underwater.
Because it's the least visible underwater and has good abrasion resistance, you'll often see fluorocarbon used as a leader line. But fluorocarbon is considerably more expensive than monofilament. So if you find it difficult to justify the cost of fluorocarbon, a clear monofilament will do the job almost as well.
If you are concerned about fish getting spooked by your line, consider this: Fish have adapted to see very well underwater. If we can see a clear leader underwater, so can a fish. But making your line less visible may make it less likely to spook a fish.
Monofilament and fluorocarbon line have memory.
This means that monofilament and fluorocarbon fishing line will retain the coiled shape of its spool. Over time, this can affect casting distance, or reduce line sensitivity. You may have seen line memory before if you've witnessed a bird's nest from line springing off the spool of a spinning reel. This can be mitigated by tightly winding your spinning reel, using line from a larger diameter spool, and keeping your line stored in a cool place out of direct sunlight.
Braided fishing line doesn't have a memory due to its multi-strand construction.
What fishing line should I use?
As with most complicated questions, there isn't really an answer that is correct in 100% of situations. But here's some good rules of thumb:
- Braided fishing line is best for baitcasting reels or conventional fishing reels, as a main line in situations where you want high test strength, don't have to worry about abrasion from underwater structure, and want instant feedback.
- Fluorocarbon line is best when used as a clear leader, or when you want a line with good abrasion resistance and low underwater visibility.
- Monofilament can make a good leader material when you need low visibility and good abrasion resistance. It remains a good budget option at the lowest cost per foot for both leader material and main line. In situations where very high tensile strength is not required, monofilament may make more sense than braid, such as on ultralight and light spinning reels.