How to Hide Your Fishing Line for Carp: Slack Lines, Backleads, Fluorocarbon and Line Lay

Bumping into something that can't be seen will make any animal very wary, and we'd react exactly the same way.

The same applies to seeing something that clearly shouldn't be there or appears unnatural.

When it comes to carp fishing, hiding your main line so that fish are less likely to see it or bump into it allows them to feed with far more confidence over your baited area, ultimately resulting in more bites.

Why are Carp so Wary of Fishing Lines?

Carp become wary of fishing lines for two very different reasons and depending on the type of lake you’re fishing.

Some of that caution is instinctive, while some is learned through repeated capture and angling pressure.

If you are on a wild water where the fish see very little pressure, then they won’t encounter anglers lines very often, and when they do it will come as a shock and will signal danger, purely on the basis that the carp won’t have experienced it before.

In nature there are very few straight lines, and especially so in a lake – sticks, weed stems and the like aren’t perfectly straight like a taut fishing line is. So anything that does appear like that, including your leader or tubing on the lakebed if it doesn’t blend in, is immediately very obvious to fish.

These sort of fish that don’t regularly swim into, and feel, line on their flanks, are likely to react badly and spook if they do suddenly experience that, and it could easily lead to them avoiding your spots or even that whole area of the lake.

On busy day ticket, club and syndicate lakes, the opposite is true in terms of how often the carp encounter your line, as they are constantly swimming around them and occasionally bumping into them, to the point where they probably accept it as part of their natural environment.

That doesn’t mean that they don’t associate lines with danger though, they just react in a different way as it isn’t a new experience for them, and they learn that when there are lines, there are also anglers and that any food in the area is likely to be dangerous. On these types of lakes that doesn’t mean that they won’t eat your bait, as competition for food is often high, and especially if stocking levels are higher, but it will change the way that they will feed and how cautious they are.

The less aware carp are of your line, whether visually or by physically contacting it, the more confidently they're likely to feed. On waters where line avoidance is a significant factor, that increased confidence can translate directly into more bites.

There isn't one single way to hide your line. Instead, different tactics reduce its visibility or the chances of carp coming into contact with it. Depending on the lakebed, depth, range and the behaviour of the fish, that might mean fishing slack lines, pinning your line down with back leads, using a fluorocarbon main line, or simply thinking more carefully about where your line enters the water and how it lies across the lakebed.

Understanding Line Lay and Why it Matters

Line lay simply refers to how your line behaves in the water and the way that it lays across the lakebed, and anything inbetween you and your rig.

Having all of your line, from your rod tip to your rig, laying tight to the bottom and completely out of the way of carp moving about in your swim, would be the ideal scenario, but in most cases is completely impractical.

If you are fishing at shorter range, and with a fairly flat, snag-free lakebed, then you can fish with your main line like this, but in most other scenarios either debris on the bottom, or the need for good bite indication, make it impractical.

Virtually all types of main line – with the exception of floating or neutral buoyancy braids – are denser than water, and will therefore naturally sink to the bottom if allowed to do so, and there is enough slack in the line.

That actually requires a lot of slack to achieve as a line laying along the bottom is longer than one cutting through the water from your rod tip directly to your rig, even allowing for the fact that it will sag in a curve, rather than being dead straight.

So, if you are going to fish with a slack line, once you’ve cast out and your rig is in place, you will need to keep paying out a bit of slack at a time until it has sunk as much as you want it to. Line sinks surprisingly slowly, especially immediately after casting. Monofilament lines absorb water over time, which increases their rate of sink, although different lines vary considerably and some long range monofilaments are specifically designed to minimise water absorption to reduce the additional weight over long distances.

Because you have so much extra line out though, it greatly reduces the sensitivity of your set-up and the ability for movement at the rig end to be transferred back to the bank and your bite indication system. So, bite detection definitely suffers when fishing slack lines, and especially so when you get a bite that isn’t a typical one-toner with the carp moving off at speed once hooked. A fish kiting, or swimming back towards you might not even register any sort of bite on your buzzers and bobbins when fishing a very slack line, or it will be significantly delayed.

When fishing with slack lines, or semi-slack, it is best to use lightweight bobbins and have them positioned on the ground - otherwise the bobbin will just drag all the slack out of your line, if you keep tightening up whilst trying to set the bobbin in the conventional position near the rod blank. A lighter bobbin is also more sensitive when there is some line movement, and therefore more likely to register.

What you don't get though with a slacker line is the same sort of feedback about what is happening in your swim, as most line bites won't even show up, unless they are particularly violent.

In some situations though, bite indication will be the least of your worries, and of far more concern is what your line might be laying across on the lake bed, greatly increasing the chances of it becoming snagged or even cut off when you get a take.

If there are lots of gravel bars, and especially in waters where there are zebra mussels which tend to grow on these gravel areas, then allowing your line to run directly over them – as opposed to a tighter line potentially running over the top and clear of the lakebed – increases the chances of it being cut on the sharp edge of a mussel shell, as well as making it more likely for a mussel to clamp onto the line.

The same is true with other types of snags as well such as lily pad roots, where your line getting stuck in amongst them can often result in a breakage and the loss of a fish.

On waters where there are lots of tree stumps on the bottom – often the case on wild lakes in Europe which are dammed and areas of forest and the like have been flooded to create them – anglers actively choose lines that float or are neutral buoyancy, or even add polyball floats above their rigs, to try and prevent them getting caught up in stumps and roots. In this scenario line lay will often be terrible and will likely result in less bites, but at least when you do get one, you will have a better of landing it.

Sudden depth changes are also a big factor in terms of line lay, and how well your fishing line can follow those contours.

Fishing over the back of a steep bar, or sudden drop off, where the depth changes several feet in a very short distance, means that your line is unlikely to be lying flat on the bottom close to your rig.

The same is true when fishing over the back of weedbeds, or to holes in the weed, and especially so if that weed is up near the surface, as your line will be running over the top of it, then suddenly changing direction and going almost straight down to your rig.

This is why the addition of some sort of heavy leader, which sinks well, or a piece of rig putty or pin down weight, can really help and ensure better line lay than you would have had using your main line straight through.

How Rod Tip Position Affects Line Concealment

The way that your rod is positioned will also play a part, in terms of whether your tips are pointing up or down.

Generally, the higher your rod tips, the more line will remain suspended in the water and the greater the chance of carp encountering it. Where practical, fishing with low rod tips, or even with the tips submerged, helps keep more of your line close to the lakebed.

The exception to that is when fishing with slack lines, as you can get away with having your rod tips high if you need to – such as where there is very shallow water close in or weedbeds in the margin, and where you want your line entering the water further out from the bank. By fishing with semi slack lines, you aren’t adversely affecting your line lay nearer to your rig, unless you are fishing at very close range.

It is very easy to adjust this as long as you have a versatile rod support system that allows you to either raise the front higher than the back, or the other way around, as necessary. Changing your rod tip position alters the angle at which your line enters the water, which in turn affects how much of it remains suspended above the lakebed before it has a chance to sink.

Best Main Lines for Hiding Your Line from Carp

If we accept that in most fishing situations a line laying perfectly along the lakebed from your rod tip to your rig is completely impractical, then making the bit that can be seen less obtrusive is an advantage.

There is an argument that the fish will still potentially bump into your line and spook off of something that they can’t see, but that is likely still better than them being able to actually see it.

For that reason, monofilament nylon lines tend to be a colour that blends in well with the surroundings on most lakes, although the clearer the water, the more obvious it will be.

This is why the majority of fishing lines are either completely clear, or are a subtle green or brown colour, so that they do blend in.

You can take that a step further by using a fluorocarbon main line, which is designed so that it has a similar refractive index to water, and means that it blends in. Although that is in a perfect situation, and in practice suspended particles in the water will adhere to the line, and those become visible – again, once enough debris is on it, it will appear as a very obvious straight line in the water.

That is why when using fluorocarbon lines it is essential to clean them regularly, and if you’ve watched the Korda films, you will have seen anglers such as Danny Fairbrass winding his line back through a damp sponge after he wraps his rods up around his distance sticks, and this removes any particles that are attached to it.

Fluorocarbon also has the advantage of being much denser than nylon, so will naturally sink far better, even when fished semi-slack.

Sinking braids, such as SUB Braid, are also an option, where allowed, and are not only a subtle green colour that blends in well with weed and the typical colour of many lakes and lakebeds, but are designed to take on water and sink incredibly well.

Because braid is much suppler than either nylon or fluorocarbon, it will also follow the contours of the bottom much more closely as well, when fished slack, but still behaves like a braid when it comes to bite indication – it won’t be as instant as when fishing with a tight line, but will still show up on your bobbins and bite alarms quicker than with mono or fluorocarbon.

Using Backleads to Keep Your Line Pinned Down

Fishing very slack lines isn't always practical. They reduce bite indication, can leave your line vulnerable to underwater snags and aren't really possible at longer range. Backleads offer another way of keeping much of your line close to the lakebed whilst still allowing you to fish with more tension.

A backlead is simply a lead (using of up to an ounce or so in weight) which can be clipped onto your line at the rod tip once you have cast out. It is able to be slid down the line – how far depends on what is in the margins in from of you, as you want it to be sat on the bottom in a reasonable depth of water, and not in amongst a load of weed or similar – and then allowed to sink. It is important to know what is in front of your swim close in though, as the last thing you want is to drop your buckled into any sort of snags, or potentially something sharp that could cut your line on the take, such as rocks.

This changes the anchor point which the line from your rig back to the bank is going to – usually it would be your rod tip, but with a backlead that could be sat on the bottom in 6ft of water, and meaning that most of your main line is running tight to the bottom. By changing that anchor point and line angle, you are changing the point at which fish are most likely to bump into your line, if they do at all, and reducing the chances of that happening anywhere close to your rigs or baited spot.

Bite indication is actually better with a heavier backlead as the line will run through it, rather than lifting the backlead off the bottom and taking the angle out of your line before you get any proper bite indication. Once you hook into the fish the backlead will slide down your line towards your rig and will stay out of the way, and if it does get stuck on anything, they are designed to easily detach from your line completely.

An alternative to a standard backlead is a captive backlead, which works in exactly the same way but is designed so that when you get a bite it comes off of your line immediately.

These captive backleads actually attach to the bank (such as to your rod support system) via a cord, and the clip on them easily opens under tension when you get a take or lift up the rod.

A backlead of this sort tends to be fished just off of your rod tips and in some situations can be really heavy, up to 5oz or more, such as when fishing at extreme range in Europe. These backleads don’t just keep the line down on the bottom out of the way of the carp, but also prevent cut-offs from boats on lakes where fishing is shared with other activities such as sailing, as well as making it much easier for you if you are boat fishing yourself, and vastly reducing the risks of you catching your own lines in the motor when you come back to your swim after dropping a rig or landing a carp.

These heavy backleads also have the advantage of allowing plenty of tension on the line due to their weight, and help preventing your rods from being wiped out by things such as floating weed – if that does collect around where your line enters the water, down to the captive backlead, it is very easy to clear it off of your lines when necessary.

For the majority of fishing in the UK, a standard backlead will do the job perfectly and is all that you need, although unlike with captive backleads, you will lose some whilst playing fish, so make sure you do have spares.

Pinning Down the Last Few Feet of Line Near Your Rig

There is little point in going to all the trouble of making sure your main line is as unobtrusive as possible through your swim, if you don’t also do the same at the rig end as well.

It is rare that you will be fishing on a spot that is completely flat and without any ups and down, and because carp feed hard to the bottom, you want those last few yards of your line, the bit that is connected to your lead system and rig, to be as unobtrusive and pinned down as is possible.

The few feet directly behind your rig can benefit greatly from some sort of leader such as leadcore (or Dura Kord which relies on absorbing water rather than having a lead core in the centre) or the fused Dark Matter Tungsten ones, which are also able to follow the contours fairly well.

It is worth remembering though, that however well these leaders might appear to match the lakebed in terms of colour, in practice they still tend to stand out as a straight line, and in our Underwater filming in some situations they can be very obvious still. Typically all you need is a few feet of this type of material, as much longer sections actually start to stand out and are obvious in the water. The same is very true for tubing, even the Tungsten impregnated stuff that sinks incredibly well and is supple enough to follow the rough contours.

Another option, and one which is popular with some of the Korda Mindset anglers, is to use some sort of fluorocarbon leader made from a material such as IQ2, which sinks incredibly well, is almost invisible in water, and is supple enough not to stick up from the lakebed if it does end up lying across a large stone of bit of weed.  

To really pin everything down behind your rig, the addition of a large piece of rig putty around your leader knot – or even just on your main line if fishing that straight through – helps to pin down that end of it and prevent it from lifting up off of the bottom and potentially being obvious to the carp. During the fight these pieces of putty will ping off of the line, so will need replacing each time, but it can be well worth the effort in the right situations.

Situations where it will really help include those where good line lay is difficult, which we mentioned earlier, such as when fishing behind weedbeds, as the putty will cause everything to sink far better than a section of leadcore would do on its own (again, because you are changing the anchor point, and therefore line angle).

Where the lakebed is fairly clear, and you’re just trying to help hide your line near to your spot, some sort of flying backlead is ideal.

These sit just above your leader or tubing when you cast, and due to the drag from them, they end up flying back up your line, so they land well behind your lead. You can restrict the amount of travel they have via the addition of a stop knot up your line, just make sure it doesn’t compromise the safety of your lead system.

Changing Your Line Angle Can Be Better Than Hiding It

On busy waters this often won’t be an option, but where the carp are used to being fished for on a certain spot from a particular swim, completely changing your line angles can make a big difference.

If carp are constantly bumping into, or spotting, lines whenever they visit a certain area, then they will know that they are being fished for and sense danger, which makes them feed and behave far more warily.

If however they approach that same spot and don’t encounter any lines where they would normally expect to, then they are more likely to view it as safe to feed there, and to do so more confidently.

Hiding your lines so that they can’t bump into them or spot them helps, but only up to a point, and in some situations (although often not practical) casting to the same spot but from a completely different swim can make a big difference.

Instead of trying to make your line completely disappear, you've changed where the fish are most likely to encounter it. If they've become conditioned to approaching the spot from one direction and meeting lines there, presenting the same bait from a completely different angle can dramatically reduce that association with danger.

Obviously, only do this on waters where it is possible and you aren’t interfering with other anglers, and if you are casting across other swims to achieve this presentation, just be ready to move your rods if another angler arrives and decides to fish from those pegs.

When to Avoid Backleads and Slack Lines

One question that all of this raises is why not just use a backlead all of the time, but there is good reason why anglers don’t.

As we have already established, the use of a backlead does reduce sensitivity when it comes to bite detection.

There are also plenty of situations where it just isn’t very practical, such as where there are likely to be any sort of snags on the bottom, sudden depth changes, or the lake is weedy. If you use a backlead in these scenarios then it may well end up costing you fish.

But there are also fishing situations where the use of one is actually dangerous for the carp, and specifically so when you are casting to snags.

In any situation where you need bite indication to be as instantaneous as possible, and sort of backlead will make that worse and slower to register, meaning that the fish could easily already be in the snags before you even know you’ve had a bite.

The same applies to fishing with slack lines, as they allow the carp plenty of movement before anything even starts to register on your bite alarm or bobbin.

So, when deciding how tight or slack to have your lines, or thinking about using some sort of backlead, assess the angling situation and make sure it is not only an advantage to do so, but is also safe.

Hiding Your Fishing Line: Quick Questions

Why are carp scared of fishing lines?

Carp become wary of fishing lines either because they have never encountered them before or because they have learned to associate them with danger through angling pressure. Fish may see lines as unnatural objects or become alarmed when they physically bump into them while feeding.

Do slack lines help catch more carp?

Slack lines can help reduce the chances of carp seeing or bumping into your main line, allowing them to feed with more confidence. However, they also reduce bite indication and are not suitable in every situation, particularly where snags or weed create a risk of cut offs.

Should I use backleads when carp fishing?

Backleads are useful when you want to pin your main line to the lakebed while maintaining more tension than a very slack line. They work well on many venues but should be avoided when fishing close to snags or anywhere instant bite indication is essential.

Is fluorocarbon main line less visible to carp?

Fluorocarbon main line has a refractive index similar to water, making it less visible than standard monofilament when clean. It is also much denser, helping it sink well, although debris collecting on the line can make it more visible if it is not cleaned regularly.

What is line lay in carp fishing?

Line lay describes how your main line sits in the water between your rod tip and your rig. Good line lay keeps as much of the line as possible close to the lakebed without compromising bite indication or increasing the risk of snagging.

Do I need a leader to pin my line down near the rig?

A short leader made from leadcore, tungsten impregnated material or fluorocarbon can help the final section of line follow the contours of the lakebed more closely. Adding rig putty near the leader knot can improve this even further in situations where line lay is difficult.

When should you avoid fishing with backleads or slack lines?

Avoid backleads and very slack lines when fishing close to snags or in situations where instant bite indication is needed. Delayed indication can allow a hooked carp to reach dangerous areas before the angler has a chance to react.

Does changing your swim help hide your line from carp?

Yes. On pressured lakes where carp have become conditioned to encountering lines from a particular direction, fishing the same spot from a different swim can change the line angle and reduce the chances of fish encountering your line where they expect it.