Back when I was just a wee water-whipper, my Grandpa taught me how to build fly fishing leaders from differing lengths and diameters of catgut. Catgut leaders had to be greased with floatant when used with dry flies.
In my teens, I could construct leaders with blood knots and monofilament nylon (“mono”), which did not have to be greased. Later, thanks to Eagle Claw and better technology, tapered, knotless leaders, extruded from mono, hit the fly shops. Life was good.
In the past decade, fluorocarbon (“fluoro”, “Fluro-Flex”) knotless, tapered leaders and tippet have hit the shelves, claiming increased catch rates due to their being “invisible” to our finned quarry. Fly anglers, being the addicts they are for any new rod, reel, line, leader, fly, hat, or prayer that will bring more fish to their net, drank the Kool-Aid.
While on the sticks in my Clacka, I have heard all the arguments presented by friends and clients as to which is better…mono or fluoro? It is my opinion that the question is moot; there are fishing situations where mono is better than fluoro and vice-versa. Please allow me to present my opinions and recommendations to a candid world.
Advantages of Mono Leaders and Tippets
- Cost. Mono leaders and tippet spools are economical, up to four times less expensive than their fluorocarbon cousins. However, that is not the best reason to use mono in certain fly fishing scenarios.
- Floatability. The “hallelujah moment” that put smiles on the faces of fly anglers everywhere was when they knotted nylon leaders to their fly lines. No more greasing catgut leaders. Now, they could cast dry flies all day, and only false casted to dry out a drowned Adams. Mono tippet will not break surface tension of the water unless pulled under by a weighted fly or by the angler.
- Mono will stretch. The molecular structure of a nylon leader allows it to stretch about 10% under load. That translates to a built-in shock tippet when a toad attacks your fly. It also means that mono tippet has less memory than fluoro when it comes off the spool or out of the leader packet. Pull it between your hands or a rubber leader straightener when stringing your rod and you are good for the day.
- Knot strength. Mono is softer than fluoro. With a little bit of spit, for lubrication, before you tighten blood, double-surgeon’s, or Davy knots, they will seat better.
Advantages of Fluoro Leaders and Tippets
- Abrasion-resistance. Fluoro leaders and tippets are resilient to being cut by sharp rocks, coral, and toothy fish. Fluoro’s abrasion-resistance is the best reason to spend the extra moolah at the fly shop.
- Will not absorb water. Mono will absorb about 10% of its weight in water over time resulting in strength loss. Fluoro cannot absorb water. Fluoro’s tensile strength is superior to mono for the same diameter.
- Resistance to UV light. Fluoro is more impervious to the sun’s damaging rays than mono, making it an informed choice when fly fishing for bones in the tropics.
- Sink rate? Yeah, that question mark is not a typo. It is a myth that fluoro will pull a dry fly under. Both fluoro and mono leaders will not break the river’s surface tension. If pulled under by a beadhead nymph or weighted streamer, fluoro will sink about 5% faster than mono. Negligible? Sink rate is more a function of tippet diameter. If you want your Pat’s Rubber Legs nymph to dive to the river bottom, use the thinnest mono or fluoro tippet that you dare. Thin diameter tippet has less surface area and, therefore, is less affected by surface tension and hydraulics.
- Invisible? Nah. There are plenty of us who, being curious, have dunked fluoro in a big jar or aquarium to see if it is truly imperceptible. Human eyes and fish eyes are remarkably similar when discerning colors and foreign objects. I can see the outline of fluoro tippet every time I perform this experiment. Hungry fish are not brainiacs. Do they really suspend in the water column looking at “food” items and rejecting them if they perceive a tippet? After all, they regularly get pulled into the sunlight after inhaling a tied clump of feather and fur with a big hook sticking out its butt. Someone invent an invisible hook, then I will be impressed. Okay, enough snarky comments.
I would be remiss to discuss nylon and fluorocarbon materials without noting the fact that leaders and tippets, lost to fish and snags, will not degrade for 600 and 4,000 years, respectively. Leaders and tippets that stay in the environment as tangled messes spell injury and/or death to fish, birds, and mammals.
When you cut out that snarled mess caused by two-nymph rigs or grab someone else’s mess they left behind, stick it in your pocket. Very likely, at the takeout or parking lot, Trout Unlimited or some other conservation organization has provided a receptacle to recycle mono and fluoro. Leaders and tippet can be recycled into plastic products, most notably benches alongside river trails. If you don’t place mono/fluoro line into a recycling station, take it home and burn it in the fireplace or barbecue grill.
Recommendations and Tips
Based on my research into the advantages of mono and fluoro leaders, plus many, many years of flogging the water with a fly line, I feel confident in recommending when mono or fluoro should be used when fly fishing.
If I have spent over $4k on a bucket list trip to Turneffe Flats in Belize (dream, dream) to chase bonefish and tarpon, it is no time to get frugal with my terminal tackle. I am going to purchase and knot on the best fluoro leader and tippet for its abrasion-resistance, tensile strength, and resistance to UV rays. Trust me, if you try to use mono leader and tippet, your guide will probably refuse to leave the dock.
Here’s a thought if you are convinced that fluoro tippet is truly stealthy. Onto your mono, tapered leader, tie on a length of fluoro tippet. Don’t use a blood knot, though, tie a triple-surgeon’s knot. The hard fluoro tippet can cut into the soft mono, leading to disaster when that big smallmouth bass hits your offering.
Better yet, if you are nymphing with a bobber or euro nymphing, tie an appropriate length of tapered, mono leader to your fly line and at the terminal end, tie in a tippet ring. To the tippet ring, tie in a length of fluoro tippet. This “hybrid” leader formula also takes advantage of fluoro’s ability to withstand the gnawing jaws of toothy fish.
I use mono whenever trout, panfish, carp, etc. are targeting bugs on or near the surface. The suppleness and floatability of an inexpensive knotless, tapered, mono leader makes it ideal for casting dry flies or emergers. Being limber, it will turn over that #18 Sparkle Dun with ease. Every angler could do better throwing dry flies with an extra-long leader that can present an Elk Hair Caddis with less disturbance on the water. Yet, most knotless, tapered leaders come in 3-packs of nine-foot lengths. Buy 9-foot, 4x leaders and then tie on a 3-foot length of 5x tippet with a triple-surgeon’s knot. That knot gives you a gauge so you know when it is time to add more tippet after changing a few flies.
Like most fly anglers, as I progressed in my fly angling adventures, I went from wanting to catch some fish, to expecting to catch many fish, to now targeting big fish. Piscivorous, meat-eating fish such as brown trout, northern pike, tiger muskies, steelhead, and salmon get huge because they are apex predators. Big, carnivorous fish are in constant attack mode either inhaling smaller fish or smacking those who would dare invade their personal space. Hence, they are not leader shy.
You need a short length of mono leader/tippet through which you can receive instant feedback when Mr. Nasty grabs your Intruder or Muddler Minnow. Thousands of steelheaders every year trust Maxima Ultragreen coated mono for its abrasion-resistance and unmatched tensile strength. My standard leader formula when hunting browns with my 5 wt. spey rod, Skagit line, and T-8 sink tip is two feet of 20 lb. Maxima Ultragreen, (stiff for turning over big streamers), tied to a 1.5 mm tippet ring, and then 18 inches of 12 lb. Maxima Ultragreen, (to pull through snags), tied to an articulated streamer with a non-slip loop knot. The tippet ring makes it easy to add tippet when necessary.
Other advice which you may find helpful:
- Sunscreen and insect repellent containing DEET will eat mono and fluoro leaders. Make sure your hands are dry after using either or, better yet, wash the stuff off your hands.
- When you are getting your gear ready for each season, remember to change your leaders and tippets. Especially with mono leaders, periodically run it between your thumb and forefinger. If you feel a nick or wind knot, replace your leader or tippet.
- An improved clinch knot is bulky when used to tie on your smaller dry flies. Learn to tie a Davy knot with your mono tippet. Less bulk, same strength as a clinch knot.
Well, there you have it. I hope my research and experience with mono and fluoro leaders and tippet have been helpful to you. To me, the controversy over mono -vs- fluoro really is nonsensical. Certain fly fishing scenarios demand one or the other. And, let’s face it, fly anglers would have more fishy hookups if they concentrated on presentation, drag-free drifts, and used quality fly tying hooks that they sharpened frequently.
Jim Hissong, Content Writer & Blogger
Jim Hissong lives with his wife, Susan, and Wrigley, the fishing dog, in Mountain View, WY. He is currently president of Upper Bear River Trout Unlimited in Southwest Wyoming and a certified guide who plans to be on the sticks more often when he retires soon. Jim is a part-time product description writer and blogger for jans.com and vailvalleyanglers.com. You can encourage his blogging by contacting him at firstname.lastname@example.org.
*Post updated on May 10, 2020