top of page

The Intriguing World of Rainbow Trout History: Origins, Cutthroat Cousins, and The Steelhead Mystery

Updated: Feb 5

Rainbow trout, with their vibrant colors and remarkable adaptability, have captured the hearts of anglers around the world. Their history, unique characteristics, and close relationship with cutthroat trout and steelhead make them a captivating subject for any fly fishing enthusiast. In this blog, we'll dive into the origins of rainbow trout, explore the cutthroat connection, and unravel the enigma of steelhead.

The Origins of Rainbow Trout

Rainbow trout are native to the cool, clear waters of North America's Pacific coast, from Alaska to northern Mexico. These striking fish earned their name from the dazzling rainbow-like colors that adorn their sides, making them a sight to behold in freshwater habitats.

Originally, rainbow trout's native range was predominantly in the Pacific coastal region, where they thrived in diverse environments, from glacial rivers in Alaska to temperate streams in California. Trout and salmon co existed all along the Pacific coast. However, their adaptability and appeal to anglers as a game fish led to their introduction to various parts of the United States and beyond, turning them into one of the most widely distributed trout species globally. Fish farms and hatchery programs started growing rainbows and they now inhabit every continent except Antarctica.

Rainbow Trout Habitat Today

Rainbow trout today are often the most common sport fish that most states stock. As long as the water temperature stays below 72 degrees these fish can survive, and begin to establish their own populations of rainbow trout. While the stocking of rainbow trout means plenty if fish to catch, many argue that introducing fish outside their native range can negatively effect other native species. Here on the East Coast native brook trout can often be outcompeted by a more aggressive hatchery-bred rainbow. Naturalized rainbow trout populations cannot spawn with brooks or brown trout, however they can all coexist is the same waterway. Today all kinds of fish in North America have been moved all over, and while it is amazing to catch a trout in their native habitat, it is more meaningful to protect the quality of ecosystem for fish populations, whatever they may be.

Exploring the Cutthroat Connection

In the family tree of trout, rainbow trout share a close relationship with Cutthroat trout (Oncorhynchus clarkii). Native to western coast of North America, these popular trout are renowned for the distinctive red or orange slash marks, or "cut-throat" marks, below their lower jaw. The relationship between rainbow trout and cutthroat trout is fascinating because they can interbreed, producing hybrid offspring known as "cut-bows." These hybrids combine the characteristics of both species, often displaying the colors of a rainbow trout with the cutthroat's signature throat marks. While rainbow trout and cutthroat trout can coexist in certain habitats, they also compete for resources, making their interactions in the wild a dynamic aspect of freshwater ecosystems.

The Mystery of Steelhead

One of the most intriguing aspects of rainbow trout is the enigma of steelhead trout. Steelhead are essentially the anadromous, or migratory, form of rainbow trout. This phenomenon involves a portion of rainbow trout populations embarking on an epic journey from freshwater to the ocean and then returning to freshwater to spawn. Steelhead also leave the Great Lakes to spawn along the surrounding waterways.

Here's what sets steelhead apart from their rainbow trout counterparts:

  1. Life History: Rainbow trout are non-migratory, residing entirely in freshwater throughout their lives. In contrast, steelhead undergo a unique life history, migrating to the ocean to grow and mature before returning to their natal streams to reproduce. This migratory behavior is what distinguishes them from rainbow trout.

  2. Size: Steelhead tend to be larger on average than resident rainbow trout due to the additional growth opportunities in the ocean. They can grow to impressive sizes, often exceeding 20 pounds, while rainbow trout typically range from a few inches to a few pounds.

  3. Coloration: Steelhead often exhibit more silvery hues, especially during their ocean phase, which helps them blend in with their marine environment. When they return to freshwater to spawn, their coloration becomes more vibrant, with reddish or pink streaks on their sides.

  4. Behavior: Steelhead are known for their remarkable strength and acrobatic leaps when hooked, making them a favorite target for fly anglers seeking an exhilarating battle. Rainbow trout can also provide thrilling fishing experiences but are often more subdued in comparison.

Rainbow trout, with their rich history and captivating characteristics, have become a beloved species among anglers worldwide. The distribution of rainbow trout means that this often the first trout we come in contact with. Their connection to cutthroat trout and the mystery of steelhead migration add depth to their story and make them a subject of enduring fascination in the world of fly fishing. Here at Middle River Outfitters we only stock rainbow trout where we have found no native trout populations. These stocked trout will not survive the summer months due to water temperatures and predators and therefore have little impact on the resident wild fish species.


bottom of page