How to read the river

<img src="whieldon-fly-fishing-how-to-read-the-river.jpg" alt="fisherman on the river">  

Reading the river is one of the most essential parts to a fly anglers tool box. Water knowledge changes your whole approach to fly fishing. More expert fly anglers have river knowledge engraved in their mind because they know. That is how they catch fish. Now I have, to the best of my ability compiled what I believe to be a comprehensive collection of vital information that will help the new comer to the sport and perhaps more experienced anglers also. If you feel you can contribute to this article, please contact me directly and I will update it accordingly.

 I have compiled this blog article from a range of resources, including my research and personal experience, the experience of multiple fly anglers, and fly fishing-guides. I have filtered the most important and essential elements of getting on fish, and sifted out the clutter of information that might be interesting but not essential. My aim is to save you time, so you can go out on the water and put these points into practice.

In writing this blog article I looked for inspiration from other authors and the internet, not only from personal experience but also the experiences of other fly anglers. In no way is this article is intended to commit plagiarism. I have done my best to compile hundreds of hours of study and research into a fun read, full of tips and simple explanations. This book gives you, the fly angler, the essential knowledge that most miss when they are on the water. Hours of research, hours of practical hands-on experience of multiple fly anglers, and a number of fly-fishing guides are all compressed intothis article for you. I have also converted this article into a free e-book download and hardcover. Links are at the bottom of the article. the book is filled with great images and explanations, a handy way to read on the go rather than having to read it on the pc. To keep things meet and simple I have divided all the article into specific sections listed bellow.






Before we get into reading the river, we must first briefly look at the trout. The more we know about them the luckier we get catching them. If you want to catch more trout then you must keep in mind a few things about them:

What do trout eat?

What are lies?

What do trout see?



For those who don’t already know, trout are predators that have a surprisingly varied diet. Trout generally eat fish like minnows, bait fish, sculpins, crayfish, shrimp, water-borne insects in all their states, leaches, terrestrial insects, salamanders, fish eggs and even mice! However, they also try things that are not usually found in their natural habitat, perhaps out of curiosity or perhaps they attack them to ward them off, in defence of their lies.



In order to survive, trout need to eat, while at the same time preserving energy and staying safe. So, they stay in areas where the water is generally slower, yet they will also have a faster current above or next to them that provides oxygen and food. There are three main type of lies: feeding, sheltering and prime lies.


Tip: Trout may also be found feeding just under or behind white water.

Feeding Lies

Trout can be found almost everywhere in a river, as long as that section of water has all the essentials. Trout are known to have feeding lies in riffles, shallow riffles, in front and behind of obstructions, such as rocks or fallen trees, top ends of pools, tail ends of pools, in eddy’s, and also, believe it or not, in the middle of the river where it would appear that there is only fast water, yet thanks to the trout’s evolutionary abilities it manages to stay in the water stream by playing the currents, and expending little energy, while feeding and holding position.

Tip: from the surface, a spot may seem too shallow to hold trout; this is due to water refraction. But in reality, it might be just deep enough to hold a substantial amount of trout. Many anglers will overlook this section of water because it “looks” too shallow.


Tip: trout can sense vibrations in the water, so move slowly if you are wading.

Sheltering Lies

These are places where a trout may be close to a safe refuge, where at the sight of any predator, it can bolt into and hide.

Tip: generally, all trout in a pool will take shelter if a single trout reacts to a predator, even the smallest of trout can sound the alarm. Keep that in mind. Many a trout may shelter under the same rock

Tip: a trout that is spooked may not reappear again for up to 30 minutes or more.


Tip: if you keep a low profile you have less chance of being spotted and recognised as a predator.

Prime Lies

These are a combination of sheltering lies and feeding lies, basically where a trout has everything it needs, including shelter and food. Lots of trout may share the lie, but larger trout may start to become dominant and possessive.

Tip: trout live in a world where currents constantly change. So, expect them to move as the current changes.

Tip: due to currents, some trout in a pool might be looking downstream, depending on what direction their source of food is coming from. Keep that in mind next time you step close to a new pool.




The pupils of trout have evolved to not be round, rather cone shaped to benefit their forward vision.  They can also move each eye separately. These factors benefit their feeding process. If we want to stalk a trout successfully, it is crucial to understand what they actually see.  This is determined by their eye position, the clarity of the water, and at what depth they are found.

Trout have cone shaped vision that gives them a circular view of the surface. This circular view as a rule of thumb is generally twice as wide as the trout is deep. Outside of this window, the trout sees nothing above the water surface around that window.  They will see something that appears either dark or like a mirror depending on how the light reflects on the water.


Tip: Trout’s Window. Outside of this window, the trout sees nothing above the water surface around that window.  They will see something that appears either dark or like a mirror depending on how the light reflects on the water

Another important note to keep in mind is that the trout’s vision around the window extends quite low to the horizon. In the image above we see that the closer we get to our friend the trout the more chance we have of being spotted.  A good rule of thumb is, you have a good chance of getting within 8-12 metres to a trout without being spotted. But if you crouch low, and where good stealthy clothes you should be able to get within 5-6 metres.

Tip: make sure that your tippet has sunken, otherwise it is visible to a trout. This will help increase your odds, especially on cloudy days.



Reading the water is an important part of river knowledge. Each river is different, but with a little help you will find that they all have similarities to observe.



Signs of clear water generally indicate a healthy river system rich in nutrients. If the rocks have algae on them in some cases this is a good indicator of a fertile river system. Then check for insect life, both on the margins of the river and under rocks. If all of these factors are positive, you know this is a good water.




A river might look clear from above, but because of light hitting particles suspended in the water, when you look underneath you will find that the visibility is not as clear as it appears from the surface. However, trout seam to manage quite well in these conditions.




Darker water can indicate a high build-up of leaves and other material, and may indicate that it is less fertile and less oxygenated than clearer water. Again, check for insect life around the bank and under rocks. If there are no rocks, and you are fishing in a sandy, muddy river, this doesn’t necessarily mean it’s not a healthy river.

Sandy, muddy bottoms are great for midge life, an essential meal for bigger insects such as dragon flies; and, of course, trout eat both. Look for slower water and foam lines, and make sure you fish the slow banks well before moving on to pools.




Trout have a tendency to position themselves in fewer places when the water is clear and low, and generally speaking, with low water there also is a slower current. Look for foam lines in the slower current if you can’t spot fish for them.

Tip: look for deeper pockets in that low, clear water; these often contain fish.




Generally speaking, fishing in high water might seem like a daunting task, but you would be surprised how well trout can see. Even if the river is moving quickly, the trout will stay in areas where the water is slower. Most probably they will not be near the fast water in the middle of the river, unless there is a current that enables them to hold their position and feed in the faster water without expending too much energy.

But generally, keep to the banks, as trout may take a dry fly if they can see it, however, fishing with streamers will increase your odds of catching a trout in these conditions. Remember to keep safe, and it’s probably best not to enter the river, if you can avoid it. Fish near banks and slower water.




You might be lucky enough to live near a river that, from time to time, develops milky coloured water.  This can be caused by high levels of lime in the rocks and a rich ecosystem. Generally speaking, water that is milky-transparent and not white indicates it’s a great time to go out and try your luck




The water current plays perhaps the biggest role in the trout’s life, bringing oxygen and food, and it shapes the whole world that surrounds it. Trout have evolved to face the current, whatever the direction. A current, along with its surrounding obstructions creates shelves, seams, riffles, eddy’s, foam lines and lies.

Currents carve impressions in the front, rear and sides of rocks, which create pockets where the water slows down before coming into contact with the rock. This slow-running water, with a faster current nearby, is a great place to look for trout.




Rain storms, spring run-offs, and dams can create very murky water that is full of material such as leaves twigs, etc. If there is an excessive amount, it’s best to come back another day, as the trout have plenty going on, and you are going to be spending most of your time getting debris off your fly’s.

However, if you do want to fish the area, look for pockets of slower-running water and foam lines, and areas close to the bank where the water is slower and away from the main current carrying all the debris.




This is perhaps one of the most important things that anglers almost never do! Read the river before stepping into it.



A great way to start is to research the section of water you wish to fish using a satellite image before even leaving the house. A warm cup of tea or coffee close at hand will go a long way while you have a good look at the satellite image of the river.

If you just step onto the river and start casting, you potentially could be casting into areas where there are no fish, and you will end up walking for miles on end in hopes that you get into fish. Sure, this may work! You will catch fish! But you are far better off doing your research. Find the best possible areas where trout may be and concentrate on those areas first.

Break the river down into segments, and look for separate pools, pockets of water, large rocks, open water, large slow bends, small bends, riffles, white water, and seams. Find segments you feel will have better chances of holding fish lies, and start there.




So, you have done your prep work. You have numbered or highlighted the sections to tackle first. You are now heading to the water, but before you get too close, make sure you get a good look at the water you are going to approach, perhaps from a vantage point or a little further back. Take a moment to break down each section. Think how you are going to tackle each part, before you start. A satellite image is a great start, but seeing the river with your own eyes is really the best approach. Keep in mind, you are looking for sections of the river where trout may be located and feeding.  Remember that your first cast is going to be your best chance of getting on a fish, so good preparation accompanied by good presentation and fly choice is fundamental. Make sure you get it all right the first time.

Tip: don’t forget to have fun, before approaching the river, take in a breath of fresh air and be happy that you are on the water. People forget this and take it for granted, but this will all make sense once you have done your prep work, and analysed the river section, selected your starting point, got your first cast in, presented it right and caught your first fish. All of a sudden that big, deep breath at the beginning of the day seems to make everything more fun, less serious, and more pleasurable.



Breaking apart a pool is a matter of looking at the currents, seeing where they go and how they move. As mentioned earlier, trout prefer to live in slower water with current close by so they can nip in and out for food and preserve energy. When breaking apart a pool, look at the: tail, middle and top sections of it.


Tip: your approach is key. Keep in mind, if one trout is spooked, they all spook! So, stay low with slow movements, and cast from a little further back, and you’ll have the upper hand.

Tail end

The tail end of a pool will often, during a hatch, hold the biggest fish, because the current is concentrated in a smaller space, and with it, all the food. Larger trout will hang around in the slower parts of the tail end close to the current.


Middle section

Middle sections of pools generally hold trout too. Look for the seams, bubble lines, large rocks, and any section that has slow water with a faster current running close by. Pick out the current that is most likely to carry food to a spot you believe to be a fish lie.

If the pool is large and slow moving and you have spotted a fish that doesn’t appear active, a well-presented fly or streamer might just get the fish moving and trigger a response.


Tip: The trout can be near the white water or even underneath it if the current allows it. So, give it a try.

Top Section

This section will often hold a good number of fish. A current that has been squeezed through the tail end of the last pool generally digs a shelf; that current will then pour into that section oxygenating the top end. The trout will stay under the shelf, or near it in a slow current, often just behind, to the side, or under the main current.

Tip: white water at the top of a pool is also an excellent place to start, as white water generates oxygen and food.




Top sections of pools can also be found on a river bend. Keeping this in mind, aim for the slower section of the bend, generally on the inside. However, if the current is slow then fish will concentrate in the middle or on the outside of the bend. That is where all the food is being carried by the current.




Large, deep rivers can look daunting, but they often hold sizeable fish and can be great fun. Break apart each section of the river you wish to fish. Look for slower and shallower sections of water. Look for structures in the current that create riffles, and look for areas that resemble a safe trout lie. Look for a slow current near a fast current. Look for any safety zones like rocks, trees, vegetation, or even shadows. Fishing from a drift boat is a great option if available.

Tip: big rivers often have a central thread that creates a foam line. That is where the trout’s food is carried and concentrated. Aim for that.




Rivers with higher sections of bank can provide shelter and slower current for trout. Look for large rocks, fallen trees and sections of shade that provide safety. Then look for any bubble line or current line that can bring food to those protected safety areas.

Tip: try not to “appear” over the edge of the river bank, but remain stealthy, and approach from an angle that does not spook the fish. If this cannot be done, blend into your surroundings as best you can and cast from further back.




Pocket water is my favourite water to fish, it’s also where I learned to fly fish. It’s great fun to fish with lots and lots of big boulders, meandering currents, and fun angles. Your senses are overwhelmed with where to start because each pocket looks like it’s going to hold fish.

Tip: break apart the sections, and look for pools. Start at the tail end and work your way up.

Tip: use the rocks to your advantage, camouflage yourself against the natural surroundings.

Tip: follow the currents, using them to your advantage, spotting where and how the fish move around the rocks. Concentrate on places that are most likely to hold fish.




If you put into practice the information I have shared with you in this book, accompanied with good presentation and correct fly selection, you will significantly increase your chances of getting onto fish. However, I believe stealth is important, and I’ll cover it in this chapter. Stealth will greatly enhance your odds of landing those spooky trout.

Trout have a window of visibility that they can see from the water, and they will flee if any sudden or rapid movement alerts them to danger. Trout also sense vibrations in the water, and to make life even harder for the angler, in general, if one trout in a pool is spooked, the rest will also run for cover. So, being stealthy is crucial.



Approaching a trout from behind is probably your best chance of not being seen, however if you approach the lie slowly using the natural background to your advantage, your chances of catching a spooky fish increase. Casting from further away on your approach also really helps, especially when approaching the tail section of a pool.

Tip: your first cast is generally your best chance to catch a fish, so make sure you have all the odds in your favour. Knowledge, stealth, presentation and fly selection are your best friends.




Picture yourself as a trout looking up from the river bottom; depending on the river, you will see either no bank with just sky as a backdrop, a bank, a forested covered area or large rocks. It is important that we, as anglers, blend into the natural environment. Dark green colours tend to help a lot when fishing banked rivers, and forested areas, and lighter clothes help blend into more open spaces. As a rule of thumb, I also wear green, as this is a common denominator.

Tip: I always wear a cap or hat in natural or darker colours, and polarised glasses, which not only reduce glare, and protect your face, but they also cover more of your skin, helping you blend in even more and see the fish better.




Use the natural surroundings to help you. A trout is less lightly to see you if you blend into the backdrop, and if you move slowly. Instead of exposing yourself in the foreground, use the rocks, trees and backdrop to aid your movements. When you stop, it helps to make sure you are well-blended into the environment, especially if you plan to cast a lot in that section.

This is not always possible, so keep abrupt movements to a minimum, if you are very visible. In this situation, cast less, and cast to catch. Don’t cast endlessly and hope… You know what I mean.


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I hope you enjoyed the read, and that it didn’t take up too much of your time. My aim is to inspire you to get out in the open and put into practice the information and tips that I’ve shared.

Get out on the water, catch those fish, send them home and tell your friends about this awesome book.

Tight lines! From your friends over at WHIELDON FLY FISHING Made for fly fishing, born to fly fish. We strive to share our passion for fly fishing through our unique products range, videos, blog, and one of a kind fishing Holidays to Lake Como.


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