Monofilament Fishing Line: How to Choose the Right One
History, Chemistry, and Everything Else That Doesn't Affect You
Monofilament (or Mono for short) was one of the first modern fishing lines. Developed by Dupont back in the late '30s, it consisted of a single extruded polymer filament. The original polymer used was nylon; companies have since experimented with countless other combinations of polymers to achieve different characteristics in fishing line. In order to be extruded, the polymer charge must be melted, allowing monofilament lines to take on a wide variety of colors, with clear, blue, and green being some of the most common. Since the line is just a single strand of polymer, the strength of the line is directly related to the thickness of the line. To achieve higher strength, a thicker line must be used.
Characteristics of Monofilament
Rather than a list of pros and cons, I'm just going to characterize each type of line as I go, as some characteristics are a pro in one circumstance, and a con in another.
- Stretchy: Monofilament stretches, a lot. This stretch means the line is more forgiving when fighting fish and pulling lures through weeds (or overhanging branches, depending on your casting ability). The line acts as a shock absorber, meaning less stress on your rod, and on the fish. In the case of fish with weak-skinned mouths, say kokanee, this can help keep them on the line.
- Inexpensive: While you can dump a lot of money on 'designer' mono, most lines are pretty inexpensive. This means that if you break your line on a snag or get a tangle, or a fish spools you, you aren't out a great deal of money.
- Good Knot Strength: Pretty straightforward; the relative stickiness of the line helps knots hold well. However, always remember to wet any knots before pulling them tight to lubricate the line. A well-tied knot will generally hold 80 to 95% of the test strength with monofilament.
- Clear: Monofilament line is relatively clear, making it harder for fish to see under water. However, it does have a slightly different index of refraction than water (meaning light bends when passing through it), so it is not completely invisible.
- Poor Abrasion Resistance: Monofilament is fairly susceptible to abrasion, so any points that have become chipped or rough severely limit the strength of the line. Always check your line for these signs of wear
- Quiet: Both when casting and retrieving, mono line is easy on rod and reel guides, meaning less noise. (This may not seem like that big of a deal, but some would argue that when retrieving a lure a noisy line can spook fish).
- Relatively High Line Memory: This is mostly a bad thing. The line wants to stay in a certain orientation, making it somewhat difficult to work with new line. Also, if the line becomes twisted, it loves to wrap around rod tips and guides.
- Very Stiff at Higher Strengths: At strengths above 20lb test, monofilament becomes quite difficult to cast.
When to Choose Monofilament
The answer for the average angler is: most, if not all, of the time. It's the perfect beginning line, due to its price, knot strength, and forgiving nature. Nearly all smaller fish—trout, panfish, most bass, and related fish—can all be caught using monofilament. It is the default line of most anglers, so if you are not really sure, just go with mono.
While there are a vast number of mono lines to choose from, some of my favorites are P-Line CX and Trilene XL. Both of these lines have a slightly smaller diameter than similar strength lines, and are smooth-casting and reliable.
What Pound Test?
The "test" of a line refers to how much weight it can hold, sorta. The truth is, most lines will far exceed this value, while some cheap ones might not even make it to their test value. There are numerous factors that dictate the actual strength including whether the line is wet or not, the age of the line, and where it's been stored. In the case you have absolutely no idea what you need, here are some general suggestions.
Recommended Pound Test for Monofilament Line
Recommended Pound Test
Trout and Panfish
Large Predators (Muskie, Pike)
20 and up
12 and up
Salmon (most rivers)
Salmon (salt water)
25 and up
Again these are just suggestions: numerous exceptions and personal preferences apply.