Fishing Line Explained: Mono, Braid, Fluorocarbon & Breaking Strain

Quick Answer

Monofilament is the default for most UK fishing and the right first choice. Braid has almost no stretch, which suits feeder work and lure fishing but gets banned on plenty of commercials. Fluorocarbon is for hooklinks and leaders rather than mainline. Match the breaking strain to the fish and the snags in front of you, not to your ambition.

Monofilament, Braid or Fluorocarbon?

Quick answer: mono for the reel, braid when you need to feel everything, fluoro at the business end.

Monofilament is a single strand of nylon and the line most anglers should have on the reel. It stretches by roughly a fifth of its length, and that stretch cushions the lunges of a hooked fish and forgives a slipping clutch or a heavy hand. Its weakness is age: sunlight degrades it whether you fish or not, so a spool wants replacing about once a season.

Braid is many fine fibres woven together. It has almost no stretch, which means you feel every knock and can strike at range, and it is far thinner than mono of the same strength, so it casts further and cuts through wind. The lack of stretch is also the problem — it pulls hooks out of soft mouths, and many commercial fisheries ban it as mainline because of the damage it does when it cuts.

Fluorocarbon is denser than nylon, so it sinks, and it has a refractive index close to water, so it is far harder for fish to see. It is stiffer and pricier than mono, which is why it is used mostly as a hooklink or leader rather than filling a whole spool.

Line type	Stretch	Visibility	Best used as	Watch out for
Monofilament	High	Moderate	Mainline for most fishing	Degrades in sunlight; replace yearly
Braid	Almost none	High unless coloured	Feeder and lure mainline	Banned on many commercials; pulls hooks
Fluorocarbon	Low	Very low underwater	Hooklinks and leaders	Stiff, sinks, costs more per metre

That is the whole mono vs braid vs fluorocarbon question in three rows. If you only buy one, buy mono.

Fishing Line Breaking Strain Chart

Quick answer: 3–4lb for silvers, 5–8lb for commercial carp, 12–15lb for specimen carp, and braid with a wire trace for pike.

This fishing line breaking strain chart covers the situations a UK angler actually meets, from a canal in winter to a pike water in October.

Target	Mainline	Hooklink	Line type	Notes
Silverfish, canal	2–3lb	1–1.5lb	Mono	Light float work, shy bites
Roach and skimmers, commercial	3–4lb	2–3lb	Mono	Standard silverfish setup
F1s	4–5lb	3–4lb	Mono	Stronger than it looks for the size
Commercial carp, float	5–6lb	4–5lb	Mono	Keep a bend in the rod
Commercial carp, method feeder	6–8lb	6–8lb	Mono	Self-hooking rig needs a strong hooklink
Tench and bream	6–8lb	5–6lb	Mono	Often fished in weed
Chub	6–8lb	4–6lb	Mono or fluoro	Fluoro hooklink in clear rivers
Barbel	10–12lb	8–10lb	Mono	Abrasion resistance matters most
Specimen carp	12–15lb	15–25lb	Mono main, coated braid link	Heavier link than mainline is normal
Perch on lures	10–15lb braid	8–10lb fluoro leader	Braid + fluoro	Leader keeps the braid off the teeth
Pike on lures	30–40lb braid	20–30lb wire trace	Braid + wire	Wire is not optional
Pike on deadbaits	15lb mono or 30lb braid	20–30lb wire trace	Mono or braid + wire	Wire is not optional

These are starting points and conditions move them. Fish clear, open water and you can drop a grade and get more bites. Fish snags, lilies or gravel bars and you go up, because losing a fish in a snag is worse than not hooking it.

The question we get asked most across the counter is what line for carp, and the answer splits cleanly by venue rather than by fish. Six to eight pounds covers a commercial fishery; twelve to fifteen is for waters holding genuine specimens. Our method feeder guide and float fishing guide both use the strengths in the rows above.

Hooklink strength and hook size get chosen together rather than separately, so read this alongside our hook sizes guide. On the pike rows, the wire trace is a fish-welfare requirement rather than a preference — our pike fishing guide explains why, and you will find wire traces in the predator range.

What Does Breaking Strain Actually Mean?

Quick answer: it is a lab figure for a dry, knotless, undamaged sample pulled straight — not what your line holds on the bank.

It is measured under conditions you will never fish in. The sample is new, dry, straight and has no knot in it. Everything you do to line after that point takes strength away from it, and nothing you do puts any back.

Knots are the biggest loss. A well-tied knot might keep 90% of the stated strain; a badly tied one can fail at half. Add abrasion from gravel, wear from rod rings, and a season of sunlight, and the number on the spool starts to look optimistic.

Diameter is the specification most people ignore and the one that changes how the line fishes. Two 8lb lines from different makers can differ noticeably in thickness, and the thinner one will cast further, sink quicker and behave better in tow. When you are comparing spools, compare the millimetres as well as the pounds.

How Often Should You Change Your Line?

Quick answer: mainline once a season if you fish regularly, sooner if it has seen sun, snags or heavy casting.

What kills line is not use, it is exposure. Ultraviolet light breaks nylon down whether the reel is on the bank or in the garage window, and heat in a car boot through summer does the same job faster. Abrasion from gravel, rod rings and the lip of a spool finishes the last few metres first.

The test costs nothing. Run the last few metres through your fingers before every session, and if it feels rough, crackly or has a memory of the spool it will not shake off, strip it back and retie. Most line failures happen in the bottom rod length, which is exactly the bit you can check in ten seconds.

Line is the cheapest thing on the rod and the only thing between you and the fish. Nobody has ever regretted stripping a spool back a week early.

Mainline, Hooklink or Leader — What's the Difference?

Quick answer: mainline fills the reel, the hooklink carries the hook, and a leader sits between the two.

Mainline is what goes on the spool and runs from reel to rig. It does the casting and takes the strain of the fight. For carp specifically, our mainlines overview covers the choices in more detail than we will here.

Hooklink is the short length between your rig and the hook, usually a few inches to a foot. It is often a different material and sometimes a different strength to the mainline, chosen to suit the bait and the lakebed. Our carp rigs guide covers which hooklink suits which rig, and you will find hooklinks and leaders in the carp range.

A leader is a length of stronger or less visible line joined between mainline and rig. A fluorocarbon leader hides the last few feet from wary fish; a shock leader takes the force of a big cast so the mainline does not crack off.

You need a shock leader when you are casting heavy leads a long way on light mainline. You do not need one for normal commercial fishing at forty yards with a method feeder, and adding one just puts an extra knot through the rings.

There is a fourth category worth knowing. For pike and zander, a wire trace replaces the nylon leader entirely, because no strength of nylon survives contact with those teeth. That one is a fish-welfare requirement rather than a preference, and it is the reason every pike row in the chart above ends the same way.

What Most Anglers Get Wrong

Quick answer: trusting the number on the spool.

1. Assuming the stated breaking strain is what you get. A badly tied knot fails at half the number on the label. Learn to tie two knots properly and you gain more strength than moving up a grade ever will.
2. Fishing far heavier than the venue needs. Thick line casts shorter, shows more and costs bites on pressured commercials. Match the line to the fish and the snags, not to the biggest carp you have ever seen a photo of.
3. Wetting nothing before tightening a knot. A dry knot burns the line as it beds down and fails early. Wet it every time.
4. Leaving line on the reel for years. Mono degrades in sunlight whether you fish or not. A spool costs a few pounds; a lost fish costs the session.
5. Using braid where it is banned or unsuitable. Many commercial fisheries prohibit braided mainline because of the damage it does when it cuts. Always check the rules at the gate.

FAQs

What breaking strain line should I use for carp?
Use 6–8lb mainline for commercial carp and 12–15lb for specimen carp. On a commercial fishery with a method feeder, 6–8lb covers everything you are likely to hook. Step up only if the water is genuinely snaggy or holds fish well into the twenties.

Is braid better than mono?
Neither is better; they do different jobs. Braid gives you no stretch, thinner diameter and better bite detection, which suits feeder fishing and lure work. Mono gives you stretch that cushions the fight and forgives mistakes, and it is allowed everywhere, which braid is not.

What is fluorocarbon line used for?
Mostly for hooklinks and leaders rather than mainline. It sinks, resists abrasion and is far harder for fish to see underwater, which makes it useful for the last few feet in clear water. It is stiffer and more expensive than nylon, so filling a whole spool with it is rarely worth the money.

How often should I change my fishing line?
Once a season for a regular angler, and sooner if the line has been in sunlight, dragged through snags or cast heavily. Run the last few metres through your fingers before each session and strip it back if it feels rough. The bottom rod length wears first and is where most breakages start.

What line should a beginner use?
Start with 4–6lb monofilament on a 3000 size reel, which covers silverfish, F1s and commercial carp. It is cheap, forgiving, and allowed on every water in the country. Our beginner tackle guide covers the rest of the setup.

Can I use braid on any fishery?
No. Many commercial fisheries ban braided mainline outright because it cuts rather than stretches, and some restrict it to hooklinks only. Always check the fishery's rules before you spool up, because arriving with the wrong line means either fishing badly or not fishing at all.

Does line colour matter?
Less than most anglers think, and mostly at the hook end. A clear or low-visibility hooklink is worth having in clear water, which is the argument for fluoro. Mainline colour matters far less, and a line you can see against the water is genuinely useful for watching for line bites.

Get Spooled Up

Mono for most things, braid where you need to feel everything, fluoro for the last few feet. Get the breaking strain right for the venue and the knots tied properly, and line stops being something you think about. Browse coarse fishing line from around £4.49 a spool, carp mainline and predator braid, or come and see us in Newmarket and we will spool your reel while you wait.

Price correct as of August 2026 — check the product page for current pricing.