Trout depend on three basic needs:
- Cover and Safety Close to where they feed. Multi-coloured, uneven, substrate with a variety of obstructions.
- Conserving Energy. Holding areas must supply comfortable current speeds and substrate.
- Food Supply Lane. Fish will move to intercept food. Moderate current speeds. Holding water and feeding lanes are often different.
Common Trout Behavior
- They don’t eat if they’re scared.
- In General Trout feed in water between 2 and 6 feet deep. In a large river, look for shallow water and in a small river or stream, look for deep water.
- They feed in water very often flowing at 1ft per second or walking speed.
- Stream trout holding in deeper water, often are not feeding.
- Trout are built to hold facing into the current (upstream)
- Trout feed Up. They are not bottom feeders.
- Trout can be suspended at any depth in a stream depending on current speeds and food available
Reading the Water
Let’s read the water, keeping in mind basic trout needs and common behavior.
Riffles
Choppy Broken Water Provides Cover both for the trout and my casting mistakes.
Riffles are often between 6 inches and 3 feet deep. Pockets and Buckets are often created in Riffles, allowing fish to hold without burning too much energy.
Many Aquatic insects lay eggs in riffles so there is good food supply.
Depth and Current Speed in addition to cover and food supply often create great conditions for feeding trout.
Shelf
A shelf is often seen directly below the riffle. It can be an abrupt or casual depth change. Shelves are also seen running parallel to the river bank or can be angled across currents.
Seams
Are found in the boundary between fast and slow current.
Seams are often created by obstructions in the water or where two currents meet and may be adjacent to the deeper part of the run. Seams offer plenty of protection close by for feeding fish.
The change in direction and current speeds are usually obvious with a visible line of well defined current. Most often, you’ll see foam bubbles on the surface pointing the way. Watch the foam line and you’ll often see tasty bugs floating in the same current line.
Fish the foam or the edge of the seam between the fast and slow water. The seam or edge is often just the right speed for feeding trout.
Head of the Pool
This is where flows and transitions from a shallow riffle or run into a deeper slower pool.
It may be a gradual change or a defined shelf.
The deep water close by provides the cover. As the water slows down, so does the food floating with it, creating ideal feeding conditions. Trout have a concentrated food source being delivered at the right speed and cover close by. The head of a pool ticks all the trout survival boxes.
Middle of the Pool
Usually, the slowest and deepest area of the pool.
Often fish holding in the middle of the pool are near the bottom and will not be actively feeding. It is also harder to present your fly to these fish. However, if you can get a tasty morsel down to these fish, they will often eat just because they can.
Tail Out
Where the water transitions from deep to shallow. Usually, the downstream end of a pool, but not always.
There may be a long flat with relatively even water depth before a tail out. Fish will often move in here to feed.
The deep water upstream provides cover close by. The food concentrates as it is forced into the shallower water and the current speed changes, offering just the right feeding conditions for a hungry trout. You will often see bugs hatching and rising fish near the tail out.
Pockets and Buckets
These are formed when areas are carved out of the river bottom. Often caused by ice gouging out a trough, they are scattered throughout the riverbed. These are often tricky to see but fish love to hold in buckets. They create an area of slower current that’s easy to hold position, deep enough so they’re not exposed to predators. Often riverbeds covered with large rocks provide ample bucket water for trout to hold in. You will also find defined pockets along the bank, or in front of and behind obvious exposed structure such as boulders and trees.
The above river features will be found anywhere in the river and will vary in size. Some will be obvious, and some will be harder to spot.
The common theme is transition. Fish love to feed in transitions because food is often concentrated, and the current speed offers trout a sweet spot for conserving energy while having the bug buffet served up.
Water Temps
Yes, this is important – Trout are cold blooded. Water temps rising increase trout metabolic efficiency to a point. Trout begin to feed at around 7C or 45F. As the temps rise, gill efficiency increases, peaking at around 17C or 63F. However, as temps rise beyond these levels, the water holds less dissolved oxygen and the trout’s gill efficiency decreases. If temperatures get too warm, trout will suffocate. As temperatures INCREASE and DECREASE towards the max efficiency range, the trout’s gill efficiency INCREASES. This means as water temps rise in the morning through the day and decrease in the evening, trout are extracting more oxygen from their environments, which in turn triggers them to be more active feeders and searchers. Basically they’re getting “espresso” jolts.
Bugs also follow hatch patterns with one of the triggers being water temps. Caddis, as an example, like temps in the 11C-13C range or 52F-54F and it’s worth knowing when the dominant bugs “should” make an appearance.
The Bow River will boast several key features and depths in the same stretch, downstream and from bank to bank. Varied current speeds, depths and substrates will present you with opportunities to test your skills. Water temps will vary and feeding fish will move into comfort zones.
As an example, during hot summer afternoons we encounter long stretches with no bug activity and no visible fish movement. We’ll move guests into faster, deeper, oxygenated water where fish are active. Around the next corner, we’ll find a shaded bank with an isolated caddis hatch and a few rising fish visible. Small pockets with the right conditions are everywhere. Pay attention out there and you’ll be amazed how many micro habitats provide opportunities for you.
Keys to Success
Take a minute to observe. Look for fish rising and bug life in the current. Are there overhead trees and bushes to worry about? Do you need to stand 10 feet back from the shore to hit the likely holding water? Don’t be afraid to get above your prospective drift line if conditions allow. Often, you’ll see trout below the surface. It pays to plan your drift line and how you’ll fish it. From the right fly, to where you’ll stand, what cast you’ll use and what depth you need to be at. Use your knowledge of a trout’s basic needs and behavior to find the fish. This can be a challenge and is a big part of what makes fly fishing so engaging.
Practice How to Read The Water
Understanding how to “read the water” is essential for successful fly fishing. This skill involves observing and interpreting river conditions to identify where trout are likely to be feeding or taking cover. Key factors include recognizing areas with abundant food supply, suitable cover, and optimal energy conservation for fish. By analyzing these elements, anglers can make informed decisions about where to cast, increasing their chances of a fruitful outing.
Ready to Enhance your Fly Fishing Skills?
Join us at Bow River Fly Fishing Company for expert-guided lessons and trips designed to teach you the art of reading the water and more. Whether you’re a beginner or looking to refine your techniques, our experienced guides are here to help. Book your adventure today and embark on a journey to become a proficient angler.