How to Fly Fish: Monofilament vs. Fluorocarbon Leaders – What’s the Difference?

Different materials make for different fly presentations. Here's when to use each.

Mono & fluoro – it never hurts to carry both. | Photo by Jasper Taback.

Purchasing a trout leader isn’t always simple. You’ll have to figure out the length and diameter that you’re looking for, as well as the material that you want. At most fly shops, you’ll have two options: mono or fluoro. If you’re new to fly fishing, there’s probably no reason you’d know what either of those materials is – so here’s a little bit about both. 

Monofilament Trout Leaders

The “mono” in monofilament means that it’s made from a single strand of nylon. It floats well, stretches, and is softer than fluoro – allowing for delicate fly presentation. It’s also significantly less expensive than fluorocarbon. 

Fluorocarbon Trout Leaders

Fluorocarbon trout leaders are designed to be stiff, abrasion-resistant, and quick-sinking. The underwater visibility of fluoro is also much lower than that of mono, and it’s generally stronger and more durable – hence the higher price tag. 

When to Use Each

A general rule for leader material: Any part of your leader that you want to float should be monofilament, and any part that you want to sink should be fluorocarbon.  

For dry fly fishing, monofilament is the way to go. If you want your fly to float, you’d better be using a leader that floats – a monofilament leader will help you control your drift and present the fly in a way that looks natural. 

For nymph or streamer fishing, go with fluorocarbon. Whether you’re fishing nymphs or streamers, you want your fly to sink quickly to the desired depth in the water column – fluoro will sink a whole lot faster than mono, and it will also hold up better to the beating offered by subsurface rocks and logs. 

Mono vs. Fluoro Tippet

When it comes time to tie on tippet to the end of your leader, you’ll have a choice between mono and fluoro, as well. The same rule applies: mono for any section you want to float, and fluoro for any section you want to sink. Sometimes, you’ll use both mono and fluoro in your setup. 

Let’s say you’re fishing a dry dropper rig – the first fly needs to float, and the trail fly needs to sink. If you want your point fly to float, your leader should be made entirely of monofilament. If you want your trail fly to sink, the tippet section connecting your point and trail fly should be fluorocarbon. You get the best of both worlds. 

A Caveat For New Anglers

If you’re just starting out, there’s zero shame in using monofilament exclusively – it’s cheaper than fluoro, and it will serve you fine for any type of fishing you plan to do. When you decide that you want to step up your subsurface fly fishing game, make the switch over to fluoro. You’ll experience the added benefits, and you can decide for yourself if it’s worth the investment.