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Comparing Brook, Brown, and Rainbow Trout

When fishing in streams and rivers, you might have encountered different species of trout. Three of the most common trout species that can be found in rivers and streams across North America are brook trout, brown trout, and rainbow trout.

While these species may look similar at first glance, there are actually a number of key differences between them. In this article, we’ll take a closer look at each species, highlight their unique characteristics, and discuss how you can identify them.

What Are The 3 Main Trout Species?

Before we get into the specifics of each species, let’s take a quick look at the three main types of trout:

1. Brook Trout

Native to Eastern and Central North America, brook trout are known for their beautiful appearance and delicious flavor. They are also relatively easy to identify thanks to their distinctive spotted skin.

Brook trout are small to medium-sized fish, with most specimens reaching up to around 14 inches in length. Their bodies are typically olive or brown in color on their backs, with a yellow or orange belly. They have dark spots on their sides that help them blend in with the rocks and other debris on the stream bed.

One of the key characteristics of brook trout is their small mouth. Compared to the mouths of brown and rainbow trout, the mouth of a brook trout is diminishes in size in relation to its body.

Brook trout prefer cold, oxygen-rich waters. They are found in a variety of habitats including small streams, creeks, and bigger rivers. They are also known to inhabit lakes and ponds, especially in the northern parts of their range.

2. Brown Trout

Brown trout are also native to Europe and were introduced into North America, where they have successfully established themselves in many streams, rivers, and lakes.

These trout get their name from their brownish hue which is darker than that of a brook trout. The backs of brown trout are typically a dark olive color that fades into a yellow or white belly. They have randomly placed dark spots on their sides, which can vary in size and shape.

Brown trout have a similar size range to brook trout, with most specimens reaching up to around 14 inches in length. However, they can grow much larger than brook trout, with some reaching lengths of over 20 inches and weighing up to 40 pounds.

One of the best ways to differentiate brown trout from other species is by examining the shape of their spots. Compared to the random spots of a brook trout, the spots on a brown trout are elongated and more uniformly shaped.

Brown trout are also known for their large, coarse mouth. Their jaws are significantly wider than those of brook trout, allowing them to feed on a variety of prey items.

Like brook trout, brown trout are found in a variety of habitats. They prefer cooler water temperatures than rainbow trout and are known to thrive in slightly warmer waters than brook trout.

3. Rainbow Trout

Rainbow trout are not native to North America. Instead, they are native to the Western United States and Canada, as well as parts of Asia.

Rainbow trout are easy to recognize thanks to their vibrant silver color and the pink or red stripe that runs along their sides. This stripe is particularly noticeable in fish that are found in clearer water.

Rainbow trout get their name from this colorful stripe, which is more vibrant in spawning males. Unlike the brown and olive colors of brook and brown trout, rainbow trout have a pale yellow or white belly.

These fish also have small black spots on their backs and sides, which are smaller than the spots on brown trout. Similar to brown trout, rainbow trout have a broad mouth, allowing them to feed on a variety of prey items.

Rainbow trout are also known to grow to a larger size than both brook and brown trout. They are considered trophy fish in many fisheries and are popular among anglers.

Rainbow trout prefer cooler water temperatures than brown trout. They are also tolerant of warmer waters than either brook or brown trout which is why they are able to thrive in warmer climates across the United States.

How To Tell The Difference Between Trout Species

Now that you know more about each species, let’s go over some key differences that will help you tell them apart.

Spot Pattern

One of the easiest ways to tell different trout species apart is by looking at the pattern and shape of the spots on their sides.

As we’ve mentioned, brook trout have random spots that are different sizes. Brown trout, on the other hand, have elongated spots that are more uniform in shape and size.

Rainbow trout have smaller, more uniformed spots along their backs and sides. If you can get a good look at a trout’s spots, you can often use them to make a positive identification.


Another way to differentiate between these species is by looking at their overall color and the color of their stripes or spots.

As we’ve mentioned, brook trout have an olive or brown back with yellow or orange bellies and random dark spots.

Brown trout have a brown or olive back with yellow or white bellies and uniform, dark spots.

Rainbow trout are known for their silver bodies and bright pink or red stripes.


Size can also be a helpful indicator when trying to identify trout.

Brook trout and brown trout have a similar size range, with most fish reaching up to around 14 inches.

Rainbow trout, on the other hand, can grow larger than both brook and brown trout. They can reach lengths of over 20 inches and weigh up to 15 pounds or more.

Feeding Habits

Another distinguishing feature between these species is their feeding habits.

Brook trout have a smaller mouth compared to brown and rainbow trout. This is adapted for feeding on small insects and invertebrates.

Brown trout, with their larger mouths, are able to feed on a wider variety of prey including insects, crustaceans, and small fish.

Rainbow trout, with their broad mouths, have an even more varied diet. They can feed on insects, crustaceans, and small fish, as well as other prey items such as tadpoles and frogs.

Where You’re Fishing

The location of your fishing spot is another factor that can help you identify the species of trout you’re catching.

Since rainbow trout are able to tolerate warmer water than brook and brown trout, they are found in a wider variety of habitats. They can be found in both moving and still waters across the United States.

Brook trout and brown trout are generally found in cooler water temperatures. Brown trout prefer slightly warmer water than brook trout.

If you’re fishing in the eastern United States, you’re more likely to encounter brook trout than brown trout. Brown trout are more common in the western United States, while rainbow trout are found throughout the country.

Identifying Trout Colors

One of the key ways to identify trout is by their colour. The colours can vary depending on the exact species, as well as the environment in which they are living.

For example, brook trout that are found in more forested areas with dark, wooded banks, tend to display darker colors to help them blend into their surroundings.

While the colors of trout can vary, here are some basic color characteristics of each species:

Brook Trout
Back: Dull olive-green to brown
Bellies: Yellow or orange
Spotting: Random dark spots on sides

Brown Trout
Back: Dull olive-brown to dark brown
Bellies: White to yellow
Spotting: More uniform, darker spots that are typically bigger than those of a brook trout

Rainbow Trout
Coat: Silver
Stripes: Pink or red stripe along side

Finding Trout in Rivers and Streams

Now that you know more about the different characteristics of these trout, you may be wondering how to go about identifying them in the water.

While it can be challenging to identify a fish before you catch it, there are a few things you can look for to increase your chances of finding the species you’re after.

One of the best ways to locate trout in a river or stream is to identify likely holding water. This includes areas with slower currents, deep pools, and nearby cover.

Since different species of trout prefer different water temperatures, you can also use temperature as a clue. For example, rainbow trout are more tolerant of warmer water than either brook or brown trout. If you find a stretch of water that seems too warm for brook trout, it could be holding rainbow trout.

In addition to location and temperature, you can also listen for rising fish to locate feeding trout. Rainbows are known to be more aggressive feeders than other trout species and are less wary. If you hear rising fish in a likely spot, it could be rainbows.

Now that you know more about how to identify these trout, it’s time to get out there and put your knowledge to the test. Remember to keep your eyes peeled for tell-tale signs of each species, and you’ll soon be able to identify them with ease.

Did you find this article helpful? Are you interested in learning more about trout fishing? Be sure to check out the rest of our site for more articles on trout fishing tips and tricks!

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