15 Fun Facts About Rainbow Trout

Rainbow trout are a popular and fascinating species of fish.

rainbow trout, (Oncorhynchus mykiss), game fish of the family Salmonidae noted for its spectacular leaps and hard fighting when hooked.

Found in freshwater rivers, streams, and lakes across North America, these beautiful fish are known for their vibrant colors and acrobatic swimming patterns.

So what is it that makes this fishy little guy so popular? Let's take a closer look!


Rainbow trout can be found in over 45 countries.
They're incredibly easy to raise in fish farms, and are very adaptable to many different environments.

There are fifteen known subspecies of the rainbow trout!
Firstly, we have the originally identified rainbow trout, the Kamchatka rainbow trout, from which all others are categorized.
There are then two types of coastal forms, seven types of redband forms, three types of Kern River golden trout forms, one Mexican form, and then a mutated form called the golden rainbow trout.

Rainbow Trout are known for their vibrant colors.
One of the distinctive features of Rainbow Trout is their vibrant, rainbow-like colors. Their body ranges from olive-green to blueish-gray, and they have a pinkish lateral stripe running along their sides.

Along coastal regions like the Pacific Northwest, some rainbow trout also call the ocean home.
These ocean-loving cousins are referred to as steelhead trout, instead of rainbow trout. Their scales take on a more steel-like sheen due to their life in the ocean.
Steelhead trout are born in freshwater, and then will live most of their lives in the ocean.

Rainbow trout are excellent swimmers.
Rainbow Trout are agile and powerful swimmers, capable of reaching speeds of up to 20 miles per hour. They have a streamlined body and a strong tail fin, which allows them to navigate swiftly through the water.

Rainbow trout return to their natal streams to spawn.
After spending a few years in the ocean or a large freshwater body, adult rainbow trout return to the same streams or rivers where they were born to spawn. They display remarkable homing instincts and are capable of navigating long distances to reach their ancestral grounds.

Rainbow trout spawn in the spring.
The spawning season for rainbow trout typically takes place during the spring months when water temperatures rise and provide optimal conditions for successful reproduction. This period usually occurs between March and June.

Males develop a spawning hook during the breeding season.
Male rainbow trout develop a distinctive hook-shaped jaw, also known as a kype, during the breeding season. This adaptation helps them compete with other males for females and secure their mating opportunities.

Rainbow trout can lay thousands of eggs at a time.
The female rainbow trout then lays an absolutely insane amount of eggs – up to 3,000 eggs per kilogram that the female weighs!
The eggs then usually take around four to seven weeks to hatch.

Rainbow trout are predators.
The main part of their diet is made up of various aquatic insects, feeding on the larval, pupal, and adult forms.
Other than insects, rainbow trout are known to hunt other water-based life. This ranges from fish smaller than them to fish eggs, crayfish, and shrimp.

Rainbow trout have been farmed for food since 1870.
Rainbow trout have been farmed and introduced to rivers and lakes outside their native range since the 1880's, most famously farmed at the McLeod River and San Leandro hatcheries in California. These two hatcheries are the original source of most of the artificially bred rainbow trout across the world.
The largest producer of rainbow trout is surprisingly not the US though, it's Chile!

Rainbow trout are an invasive species.
Rainbow trout have been spread throughout the world. They are included in the top 100 of the world's worst invasive species.
Research has shown that they can displace native trout, and their sheer numbers can alter the aquatic invertebrate community, to the detriment of other fish species.

Rainbow trout cannot live in polluted water!
In fact, it's due to this that rainbow trout are actually used in water purification facilities to test pollution levels in the water.

Rainbow trout are a popular sport fish.
Rainbow Trout are highly prized by anglers for their fighting spirit and delicious taste. Many people enjoy the thrill of catching these fish on fly fishing gear or spinning tackle.

The largest recorded rainbow trout weighed 48 lbs!
The biggest rainbow trout ever caught weighted 48 pounds and was 42 inches long with a 32 inch girth. This world record was caught at Lake Diefenbaker in Canada by Sean Konrad in 2009.
It was actually an escapee from a nearby fish farm where they genetically modified their trout to increase size and weight.

Wikipedia / Soft Schools / Orvis News
Image credit: American Oceans