Fishing for Trout: Reading the Water


by Bryant J. Cochran, Jr.


The trout fisherman must be able to read a stream or river in far more detail than a canoeist, kayaker or rafter. The boat folks can see the current flow and the humps that show where rocks are, they even see the “seams” where currents of different speed run side by side. They would be hard pressed if you asked them to show you where fish might be lying. Simply because they lack detail in their knowledge. A fisherman needs to fully understand the fishes survival needs and behavior patterns in order to properly read a stream. These are the details a fisherman needs to know, that a boater doesn’t need or want to know. The subject this series will cover is easier to learn, understand and put to use than the myriad of knots, lines, casting flaws and entomology. Plus it is more entertaining in conversation than entomology, unless you are at a professors cocktail party.

You will learn where to cast along with where not to cast and why. Where to wade and where not to wade so you don’t spook the fish and have it running and spreading the alarm to the rest of the fish in the stream. You will be able to go to new waters and fish with confidence, all year long, knowing where the fish will be in any season and any conditions. Your fish location predictions will impress all but the most expert of fishermen. Given a casting technique of accuracy, your catch rate will increase and the size of your catch will increase. You will know why stealth and casting on a dime are so important. This accuracy will be the difference in the number of fish you catch especially when you face a situation where only a few inches of drag-free drift are available. Trout have very narrow feeding lanes and they will not move one extra inch for any reason.

These new skills are essential for success and one of the main areas of knowledge that separate the beginner/intermediate from the expert. As with everything, there will be times when the trout will be anywhere but where you think they should be. In these times – when conditions are just right, what you learn here may not work. When this happens – please be kind in your thoughts of me and my words. Don’t forget that we have a help line under Q & A, if you have a problem in the future or present, let me know, I will get the answer to you.


The brain of a trout is a simple one. It is small and consist of four lobes – two large and two small, these are called ganglion by biologist, they represent a very simple brain. This brain will fit on a quarter and it is primeval. The fact that many fishermen give the trout high marks for intelligence just shows how much they don’t know about biology. Simple minds have simple needs. All species of trout have three basic needs not including water, Food, Shelter, and Oxygen. In order to be a sustaining population they need a proper spawning habitat, which is usually the same as their normal living habitat. They also need deeper pools to survive a winter with anchor ice covering the habitat, unless they are in the southern tail waters of America or other countries.

In nature there are seldom any linear relationships. In order for trout to have food, the oxygen levels, water temperatures and nutrient flow, must be adequate to support the lives of the prey organisms which are; insects and their larvae, minnows and other fish, fry and the crustaceans. The trout who limit their diet to minnows, sculpins, crayfish and other trout are sometimes called sharks. The oxygen level is dependent on the water temperature and the amount of surface area that can exchange gas (O2) with the atmosphere. This equates to how much riffled or white water there is on the stream. The pools below a riffle will have a higher O2 content than the pools above the riffle. Shelter means several things to a trout. Protection from predators and protection from the main current, but close enough to feeding lanes in the current so little energy is expended in the gathering of food. This conservation of energy is extremely important to a trout, the less energy spent on feeding the more energy to spend on growth, all trout want to grow larger. When food is plentiful and gathering energy out put is small, a trout can grow at a fast pace. The larger the trout, the better home he can claim for himself.

We know how important a good food supply is but the food supply is intertwined with the need for shelter. A trout needs two types of shelter. First he (or she) needs a territory close to the main current, the current acts like a conveyor belt moving food organisms down the river. This territory will be sheltered from the current and could be a rock, tree branch, a shallow dish in the stream bed, an opening in a moss bed, or any thing else that breaks the current or slows it down. When a feeding shelter is close to or is itself a place to hide from an airborne or land based predator you have found a “prime lie” and a large trout is probably occupying it.

The life of a trout is a harrowing journey through time. As a fry he is hiding in the mossy or grassy shallows, hoping that he will avoid being eaten by birds, a host of land animals or another fish, which could even be his parents. Once he is around five inches long his predator instincts grow and the juvenile seeks deeper water and his own territory. If he finds a really good shelter/territory he may stay there for the rest of his life. More likely he will move as he grows longer, from territory to territory, until he finds a “prime lie” territory to call home. Or he might find a nice deep pool and take up a territory where no predator from above might see him, and move to the shallower feeding lies at night. This leaves the trout with other water dwelling predators as danger to himself. The really deep pools are where you will find the really big “kings of the pools”. You will only catch one of these guys if you fish at night, when they move up to feed. These are the world record type fish, and only occasionally are weather conditions right to find them cruising for food in the day light hours. On my home waters the world record brown trout was caught – it weighed in at 40 lbs. 4 oz.. I would not be surprised to hear of one significantly larger being taken in the future, especially from a tail water river like my home waters – the LITTLE RED RIVER and the WHITE RIVER both in Arkansas, USA. A trout likes water with a depth of three feet or more, you can check this by seeing how close you can wade to one that is in a depth of three feet as opposed to one in two feet of water. In a depth of three feet the trout feels safe from land or air predators. The day light hours between and including dawn and dusk is the time period most of us are going to fish. The middle fish are the active ones during this time period and they are the ones we will mostly catch. They will be wary of their surroundings, using all of their senses and their above water window of vision, they will bolt for their predator shelter at the slightest hint of danger, unless they are in the safety zone of three foot or more water depth. And once spooked they will not return to active feeding until they feel safe.

A rivers current determines where the feeding lanes will be. It is the conveyor belt bringing the trout his food. He sits in a protected place, close to the conveyor belt and reaches out to grab the food he wants. He doesn’t have to expend a lot of energy to do this and given the opportunity he will spend all of his time in his feeding lane, this is home. He will defend this territory from other trout, but if danger causes him to bolt to his protective lie, a log jam or rock pile, he allows any neighbors to crowd in, fins touching, till the danger has past. Then and only then will the trout return home and begin feeding once more. When a trout is home he is always catchable, because he will be feeding all the time he spends there. All the fisherman has to do is figure out what he is eating and where in the depth range of the stream he is feeding, bottom, middle or surface film. When the fisherman gets all of this information right, he will catch every trout he presents his fly to, provided all the rules and information he gathered are followed. Alas, every fisherman will have days when one bit of information is either lacking or not thought of and the fisherman will go home empty handed.

In the articles to come of this series I will fill the gaps in the knowledge of reading a stream or river. When we are finished you will have the information to know where to cast your fly and have the best chance to have a trout at least see your offering in the right place for the trout to want to eat it. Whether or not he will depends on the correct presentation of the fly. The fly will be in his feeding lane and that is the first huge step in the game of fly fishing. Please do make a hard copy of this series so you can go back to it time and again. Repetition does help retention. Until next month, May god guide your cast and give you good fishing.

Continue on to Part 2 of Reading the Water >>