Fluorocarbon 0r Mono?
First off, don’t be fooled by the substantially higher price tag on fluorocarbon materials when compared to monofilament. Many anglers reach for fluorocarbon under the assumption that because it is more expensive, it is a superior choice of line.
The visibility of fluorocarbon line is most likely the best selling point of fluorocarbon when compared to standard nylon monofilament line. The light refractive index of fluorocarbon is very similar to that of freshwater. In other words, when placed in water, it is less visible than monofilament.
In the short term, fluorocarbon is a much harder material than monofilament. This results in higher abrasion resistance that is useful in situations such as nymphing or fishing around heavy structure. Also, most fluorocarbon line is thinner in diameter than monofilament line of the same breaking strength. However, this is not always the case from company to company.
Fluorocarbon is also non-permeable to water and therefore does not absorb water throughout the fishing day.
For you trout fisherman out there, the density of your leader material is actually very important. Fluorocarbon is actually denser than water. In other words, it sinks... However, if dead drifting or skating flies on the surface, this is the last thing you want. Nylon monofilament on the other hand actually suspends in water. If fishing dries, especially in very small sizes, monofilament is a clear winner here. That's why it has been widely used as a shock leader, so that out there at the bottom can actually help your bait following currents
Most anglers are aware that monofilament is a relatively “stretchy” material. Just grab your leader from both ends and pull; you will see it stretch. While a certain degree of stretch is advantageous to help absorb the shock while fighting a fish, fewer stretch results in higher sensitivity for detecting those subtle takes. Fluorocarbon is said to have less stretch than most nylon monofilaments, however, there has been some debate among differing manufacturers.
I personally recommend having a fluoro terminal between 1-2 mt, depending on your fishing style. So that you can have strength and sensitivity where you need it at most...In saying that I cough 100's of fish without it :} however, learned from mistakes and also a personal preference and if you, like me, love fluoro << GET YOUR HERE>> Its a bargain for 200 yd