Ask a Naturalist: Are Steelhead trout and Rainbow trout the same species?

May 11, 2021

Written by Angie Cha

Learn

Steelhead trout and Rainbow trout live different lifestyles, but they are the same species. Steelhead trout are anadromous, meaning they start their life in freshwater, go to the ocean where they spend most of their life, and then return to freshwater to spawn. Rainbow trout are freshwater fish and spend their lives mostly or entirely in freshwater. There are some Rainbow trout who, after 1 – 3 years in their freshwater habitat, will migrate to the saltwater. At this point, the Rainbow trout becomes a Steelhead trout. 

 

Scientists are still trying to figure out what causes this change. The transition between a Rainbow trout to a Steelhead trout cannot be reversed. Once a Rainbow trout enters the saltwater, their bodies will change to adapt to the saltwater. When they return to the freshwater for spawning, their bodies do not revert and remain as Steelhead trout. The offspring, though, can become Rainbow trout if the fish are content with remaining in a freshwater habitat. The reverse can occur with two Rainbow trout; their offspring can become Steelhead if they decide to migrate to saltwater. 

 

A Steelhead trout’s body changes colors when they enter the saltwater. They also tend to be bigger in size with stronger and longer fins to help with their migration back to freshwater for spawning. In comparison, Rainbow trout are smaller and more colorful.  

Learn more about Rainbow trout and Steelhead trout by checking out this video!

 

Create

Create a movable fish by following this tutorial! This simple craft is easy, fun, and colorful! A fin-tastic craft for families!

 

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Use your imagination! If you were a Rainbow Trout, what kind of freshwater habitat would you live in? If you were a Steelhead Trout, where would you do in the Pacific Ocean?