How to Find Fish (Part 1): Reading Water

This is the first post in our series on how to find fish in any type of water. To see all the posts in this series, click here. 

By Spencer Durrant

Knowing how to look at a river, dissect it, and identify where fish are likely to be holding is as much a skill as sniffing out the best wing joint or pizza place in any small town.

I’m the kind of guy who can find great pizza and wings anywhere.  Earlier this summer, me and the rest of the VFC crew stopped for lunch while fishing in Wyoming. Everyone wanted pizza and wings (mostly me) and after a quick look through the local restaurant options, I picked a place that had the best wings I’ve ever had in Wyoming.

Alex – the guy in a lot of our weekly tips and tying videos – has a different skill set. That morning, before stopping for wings and pizza, we were on a stream that was still high with runoff. I was ready to give up on fishing, but Alex stuck it out. He found a neat little run where the water flew over a shelf and dropped into a deep pool. Alex caught a half-dozen fish from a spot I’d passed up.

Needless to say, one of us has a more useful skill than the other.

The point here, of course, is that if you struggle with finding fish in a river, you can easily get better at it. Alex didn’t wake up one morning, waltz to a stream, and immediately identify a perfect lie in the lee of a boulder. At least, I don’t think he did.

This series of posts is designed to help you cultivate that skill. By the time we’re done, you’ll be able to identify where trout should be holding in just about any river you come across.

But before we get into recognizing specific water types, we first need to know how to read water.

What is ‘reading water?’

Reading water is a term you’ve probably heard before, but do you know what it means?

In simplest terms, reading water means that you’re able to look at a piece of water and identify certain features, like seams, currents, eddies, pools, and riffles. These features tell you where fish are likely hanging out, eagerly awaiting the chance to eat your fly (or refuse it entirely, if you’re fishing in Colorado…).

Comprehension strategies

I’m an English teacher by day, so let me put this into scholastic terms for everyone. As a beginning angler, you probably have something like a 1st-grade reading level when it comes to reading water. You can sound out some words on your own, but you need help getting through books without pictures.

And that’s fine! We’ve all been there before. Just like we’ve all been in 1st grade.

And just like your teachers did back in grade school, we’ll go over some comprehension strategies to help decipher what the river is telling you (and we’ll even throw in some pictures too!). You’ll need to have a firm grasp of these basics before we move onto locating fish in specific water types. And just like with reading, the more you practice, the better you’ll become at comprehending what rivers have to tell you.

There are two strategies that you need to learn before you’re ready to check out that chapter book with dragons on it from the local library all by yourself.

Strategy #1 – Identify the Current

Currents are the building blocks of the river. Just like you need to know the alphabet to read a book (or this wonderfully helpful blog post 😜), you need to be able to recognize the current that trout will most likely call home.

Different currents form when water moves over the river bed. If a river has a uniform riverbed and banks, then the current will be almost the same across its entire width. However, most rivers have a great deal of rocks and other debris littered on the banks and on their beds. As water moves over and around the rocks and debris, that causes friction (like you might experience at dinner with your mother-in-law…) which slows down the water. It’s this friction that causes different current speeds within a river, and it’s inside those different currents that trout take up residence.

Since that friction occurs on the bottom of the river, that means water is always moving slower closer to the bottom of the river than the top. There’s less resistance up top, so the water speed isn’t as impacted by debris on the river bottom.

That same concept holds true for water near the river banks, too. Banks cause a ton of friction, slowing down the water to a leisurely pace. Out in the middle of the river, though – all bets are off! The water is flowing free and quick because the banks aren’t there to impact it’s momentum.

Remember – all these different current speeds create good and bad trout habitat. Understanding how these currents change speed is the first step to identifying great trout water where other people just see a river.

Riffles – The Perfect Example

So, what currents should you be looking for, and which ones should you try to avoid?

To help answer that, let’s look at a water type that anglers and fish both love – riffles. A riffle is formed when water flows over a collection of small rocks and gravel. The water is forced to flow to either side of the rocks, or back upstream if it hits the front of a rock. All that movement creates turbulence on the surface of the river, which us anglers see as a “riffle.”

Now, does that look like water where you’d expect to find a fish? Most new anglers would probably respond “no.” We’re all conditioned to expect fish to live in deep, slow pools. They do – but that’s not where they all live! They spend a ton of time in riffles and other fast-moving currents for one reason: food!

To quote Tom Rosenbauer’s book on reading water, “Studies have shown that trout prefer to lie in water that runs about one-quarter to one-half foot per second, and feed in water that runs about two feet per second.”

A good riffle runs about at about two feet per second, which is exactly the water speed trout are most comfortable feeding in. Riffles are also chock-full of little pockets that are perfect for trout to hang out in, because they don’t have to spend as much energy to hold there as they would in faster water. We’ll dive into holding water and riffles in greater detail in upcoming posts, but keep these facts in mind.

That’s why learning to identify currents – before we get into any of the particulars about places where trout hold – is so important. If you spend all your time fishing in water that’s too fast or too slow, you’re not likely to catch many fish.

Speed Matters

Trout want to expend the least amount of energy in return for the most amount of food (sounds like a lot of my students…). As Rosenbauer noted, trout like to feed in water that moves about two feet per second. Obviously they’ll feed in slightly slower, or slightly faster, water, but that’s the sweet spot you should be looking for.

So, what does all this mean? If fish prefer to live in water moving about a half-food per second, but like to feed in water moving at two feet per second, then we need to be looking for a current of slower water surrounded by slightly quicker water. The junction of these two currents is where trout are most likely to hang out for the majority of their time.

Strategy #2 – Recognize a Seam

Once you’ve identified water moving at about the right speed, you’re ready to learn about seams. As I alluded to at the end of the last section, the junction of slower and slightly quicker water is a place where trout are likely to spend a lot of their time. This junction is called a seam.

Seams can occur all throughout a river – next to the bank, behind a rock, or where a pool and a riffle meet. Seams provide trout with just about everything they need to be happy, like cover and easy access to food. Most importantly, water isn’t moving too quickly in a seam, so trout can hang out there without burning through too much energy.

When you start to look at a river as a collection of currents and seams, it becomes easier to know where fish are probably holding. Even big rivers – which are intimidating – are easily broken down into collections of seams.

Of course fish hold in other places, too. Pools, eddies, riffles, and pockets are just some examples of the water types we’ll cover in this series. For today, though, make sure you’re solid in your ability to identify the right kind of current for trout, as well as current seams.

I know that was a ton of information, so I’d recommend bookmarking this page and coming back to it often. In the meantime, go tie some flies while you get ready for the next post in this series – all about pocket water!