We recently received some comments on one of our web articles by a frequent website user Sammy T asking a couple of very legitimate questions:
“Are Rainbow Trout the same as Steelhead?” and “What is the difference between a large Rainbow Trout and what they all Steelhead?”
Thanks for this Sammy as it is an ongoing question/issue that constantly needs clarification.
STEELHEAD VS RAINBOW
Both fish are classed as Oncorhynchus mykiss which is the scientific name for the Rainbow Trout. So long story short, they are the same species.
That said, there is a difference.
If an “Oncorhynchus mykiss” Rainbow Trout is born and lives its entire life in a freshwater lake, river, stream, creek, or pond, then it is called/classed as a Rainbow Trout. This fish lives a simple life cycle, always in its freshwater environment.
If an “Oncorhynchus mykiss” Rainbow Trout is born in a freshwater river or creek but then migrates out to saltwater to live most of its life, then it is called/classed a Steelhead (defined as anadromous, meaning they spend part of their lives migrating to, from, and within the ocean).
This fish lives a more complex life. It hatches in fresh, running water and then usually from 1-3 years, makes the trek back downstream to saltwater. There it forages and feeds in the nutrient-rich ocean, constantly getting larger and larger (sometimes hitting the 30-pound range).
After it has lived in the ocean for several years (this can vary), these Steelhead will return to the river where they were hatched, and they too will spawn. This is similar to a salmon except they do not die after spawning.
NOW FOR THE REAL CONFUSION
Are the Rainbows that migrate from the Great Lakes tributaries back into the Great Lakes classed as Steelhead?
They do migrate the same way as the ocean fish do, the only difference is, they live their entire lives in freshwater. This is one that is argued daily among the freshwater river anglers, shore casters, and main-lake trollers.
They sure do act like a true Steelhead!
THE LOOK OF THESE FISH
Steelhead vs Rainbows can show some visible differences. Steelhead “usually” grow bigger and have more of a streamlined, torpedo look to them. Rainbows are a bit rounder with more of a snubbed off or rounded nose and face, looking more compact (something like a small hen Steelie right… wait, what??). There are, however, different “looks” to each fish (much like a short fat vs a long lean bass) so the differences are not always easy to see.
As for colours etc., a Steelhead in the ocean or the Great Lakes will have a chrome look to it without many colours. Once it enters the flowing freshwater, however, they morph into a kaleidoscope of hues, often quite different from each other in the same area. As well, they take on the pink/reddish stripe along each side that most Rainbow Trout are known for.
We find freshwater-only Rainbows almost always have some form of pink/red stripe and as well, they at times seem to have more black dots or spots on their entire body.
As for taste, they’re both delicious so long as you like Trout or Salmon to begin with.
CONCLUSION
We will leave Sammy—as well as the rest of you—with this:
A Steelhead will always be classed as a Rainbow Trout, a Rainbow Trout, however, is only sometimes classed as a Steelhead.
“HEY, did we just hear someone say, Pickerel?”