Steelhead vs Salmon: What’s the Difference?

Written by August Buck
Updated: November 6, 2022
Image Credit Dec Hogan/Shutterstock.com
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When it comes to comparing steelhead vs salmon, you may be asking yourself: what’s the difference? There are many more than you have likely considered, including the main difference in their genuses. For example, the steelhead scientific name is Oncorhynchus mykiss while salmons have many differing scientific names, depending on their breed. However, it is important to note that the primary difference between steelhead and salmon is the fact that steelhead are trout!

In this article, we will compare and contrast these two fish so that you can fully understand the ways in which they are different. You will also learn how to tell these two fish apart, though they do look strikingly similar. Let’s get started and learn more now.

Comparing Steelhead vs Salmon

Steelhead  vs Salmon

A-Z-Animals.com

SteelheadSalmon
Size25 inches maximum40 inches maximum
SpeciesTroutSalmon
AppearancePink stripe visible among speckled scales; white mouthNo pink stripe; gray and speckled body, dark mouth
Weight20 pounds, on average30-40 pounds, on average
HabitatSeas and riversSeas unless they need to spawn

The Main Differences Between Steelhead vs Salmon

steelhead vs salmon
Steelhead remain much smaller than salmon on average, measuring no more than 25 inches on average.

FedBul/Shutterstock.com

There are many key differences between steelhead vs salmon. Steelhead are trout, not salmon at all. Salmon also tend to get much larger than steelhead, depending on their specific breed of salmon. Steelhead can also only be found in the sea while salmon make their journey from the sea and upriver so that they can spawn.

Let’s discuss these differences in more detail now.

Steelhead vs Salmon: Size

One of the key differences between steelhead trout and salmon can be found in their overall size. For example, steelhead remain much smaller than salmon on average, measuring no more than 25 inches on average; salmon can grow up to 40 inches on average, depending on the type of salmon that they are.

However, given that both of these measurements are just averages, they may not help you when it comes time to identify whether or not you have caught a steelhead trout or a salmon. Both fish have the tendency to grow far beyond these measurements, as some steelhead reach over 45 inches in length, depending on their environment. This would easily confuse the average fisherman, given that salmon also grow to this length. 

While steelhead trout can be found in both seas and rivers, the trout that choose to migrate to the sea always grow larger than their river bound counterparts. However, steelhead never grow quite as large as salmon do on average, whether or not they migrate to the ocean. 

steelhead vs salmon
Steelhead trout have white mouths and gums, while just about every variety of salmon will have a dark or black mouth and gum line.

Kevin Cass/Shutterstock.com

Steelhead vs Salmon: Species

Another key difference between steelhead and salmon can be found in their basic species classification. While both fish are from the salmon family, steelhead trout are also known as rainbow trout or  Oncorhynchus mykiss. Salmon are known by a wide variety of names, depending on their specific breed, but no salmon varieties are called trout.

Steelhead vs Salmon: Appearance

Steelhead and salmon continue to differ in their overall appearance. While you may not be able to tell unless you have both fish side-by-side, steelhead usually have a skinnier body than a salmon. Many salmon species also have hooked noses, while steelhead trout will not.

Both fish varieties have speckles as well as many different colored markings, such as pink bellies and green tails. However, there is one telltale sign that you can look for in order to tell steelhead vs. salmon apart. Steelhead trout have white mouths and gums, while just about every variety of salmon will have a dark or black mouth and gum line. 

steelhead vs salmon
 While both of these fish can grow to be roughly the same size and can look strikingly similar, many different varieties of salmon often outweigh the average steelhead.

iStock.com/PerfectStills

Steelhead vs Salmon: Weight

Another key difference between steelhead vs salmon lies in their overall weight. While both of these fish can grow to be roughly the same size and can look strikingly similar, many different varieties of salmon often outweigh the average steelhead. 

For example, the average steelhead trout weighs roughly 25 pounds, though it can reach up to 50 pounds, especially if it has migrated to live in the ocean. Salmon, in contrast, weigh an average of 40 pounds, depending on the specific breed. There have even been reports of some salmon weighing as much as 80 pounds

steelhead vs salmon
Many salmon species also have hooked noses, while steelhead trout will not.

The Old Major/Shutterstock.com

Steelhead vs Salmon: Habitat and Migration Habits

The final key difference between steelhead vs salmon lies in their habitats and migration habits. We all know that salmon swim upstream in order to spawn their young before dying, and steelhead performs in much the same way. However, there’s one key difference in this process. 

Both of these fish are considered anadromous, though steelhead often choose whether they want to live in the sea or river. Salmon do not share the same luxury, living most of their life in the sea until it is time to swim upriver and spawn.

Benefits that steelhead have over salmon lie in their ability to breed more than once. Salmon species are capable of spawning upstream once before passing on, while steelhead trout are capable of spawning multiple times in a lifetime. This means that they make their treacherous journey upstream more than once, but it also means that they breed more young than the average salmon does. 

Steelehad vs Salmon - King Salmon

Dec Hogan/Shutterstock.com
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About the Author

I am a non-binary freelance writer working full-time in Oregon. Graduating Southern Oregon University with a BFA in Theatre and a specialization in creative writing, I have an invested interest in a variety of topics, particularly Pacific Northwest history. When I'm not writing personally or professionally, you can find me camping along the Oregon coast with my high school sweetheart and Chihuahua mix, or in my home kitchen, perfecting recipes in a gleaming cast iron skillet.

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