Brown Trout vs Rainbow Trout – What’s the Difference?

Brown Trout vs Rainbow Trout – whats the difference between the two?

The easiest way to tell the two fish apart is from their colouring. A brown trout is brown with reddish spots, and a rainbow trout is silver with a pink or red stripe down the side.

In this post I go through in detail all the differences in appearance between the brown vs rainbow trout, as well as their size, lifecycle, and what they taste like to eat!

Brown Trout vs Rainbow Trout

The photograph below shows the difference between a brown trout (on the left), and a rainbow trout (on the right). You can clearly see the pink stripe along the back of the rainbow trout. The brown trout has no lateral line like the rainbow trout, and has large dark red spots on its back.

You can see from the photograph that the rainbow trout and brown trout also have slightly different fins. On the brown trout, the adipose fin has spots on it, and often has an orange border.

By comparison, the adipose fin on the rainbow trout is smaller, and less distinctive. Rainbow trouts have larger anal fins compared to brown trout, and unlike the brown trout they have spots on their tails.

The diagram below will help you identify the fins on each fish.

What is the Difference Between Brown Trout and Rainbow Trout?

Appearance

The body colour of each trout can vary but the rainbow trout is usually silvery coloured, and the brown trout is usually brown or olive.

Brown Trout

Brown trouts have a golden brown body with a yellow or orange coloured belly. Unlike the rainbow trout they have no lateral line.

Brown trout have larger spots than rainbow trout. The spots are black or red, and have a pale border around them.

Rainbow Trout

The rainbow trout is more colourful compared to the brown trout. It has rainbow colours on its back and a white belly.

Rainbow trouts are also covered in spots from head to tail. They are sometimes called the “red band trout” since they always have a pink, purple or red stripe running along their bodies.

Size

Brown trout grow longer and are heavier compared to rainbow trout.

Brown Trout

On average, brown trout grow to between 15-22 inches, and weigh between approximately 0.5-2.5 kg (1-5 pounds). Although this is the average size, they are able to grow up to 9kg (20 pounds) in the right conditions.

Rainbow Trout

On average, rainbow trout grow to between 12-20 inches, and weigh between approximately 0.5-2kg (1-4 pounds). Although this is the average size, some rainbow trout can grow over 20 inches.

Habitat

Both brown and rainbow trout have a similar habitat, but brown trout are able to tolerate more temperature and turbidity variations compared to rainbow trout.

Brown Trout

Brown trout like clean, clear, and cold streams, are able to tolerate a wider range of habitats compared to both brook trout and rainbow trout.

Rainbow Trout

Rainbow trout like to live in clean, clear and cold streams.

Summary of the Differences Between Brown Trout vs Rainbow Trout

Do Brown Trout and Rainbow Trout Taste the Same?

Brown trout and rainbow trout don’t taste the same to eat. Brown trout has a much stronger flavour compared to rainbow trout, which is mild and more nutty.

Brown Trout

Brown trout has a strong fishy flavour (especially larger brown trout). Some people soak brown trout in milk overnight to reduce the flavour. Brown trout is tasty when paired with lemon, chilli, garlic, or paprika.

Rainbow Trout

Rainbow trout usually has a mild flavour, although farm raised rainbow trout are stronger and sweeter compared with those found in the wild. Rainbow trout pairs well with butter, garlic, lemon, dill or thyme.

Can Rainbow Trout and Brown Trout Breed?

Rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) are different species from the same family of fish (Salmonidae). 15-20 million years ago they had the same ancestors but since then they divided into two groups: rainbow trout became isolated in the North Pacific, and brown trout in the North Atlantic.

Since they are different species, rainbow trout and brown trout will not interbreed. The two fish can, however, be interbred in a fish farm environment. The cross between a brown and rainbow trout is called a “brownbow.”

Another hybrid of brown trout includes the tiger trout which is a mix of a female brown trout with a male brook trout.

Which Trout Fights the Hardest?

When it comes to trout fishing, rainbow trout usually put up more of a fight compared to brown trout. Rainbow trout are strong and will thrash about once they are caught.

Brown trout on the other hand are difficult to hook, but are easier to land because they put up less of a fight. Brown trout however are one of the smartest, most difficult trout species to catch.

What are the Different Types of Trout?

There are around fifty different species of trout. Some fish that we call “trout”, however, such as brook trout, bull trout and lake trout are actually not trout, but char.

Char can be distinguished from trout by their colouring. Whereas trout have light bodies and dark spots, char have dark bodies and light spots.

Brown trout and sea trout are both native to the UK. Sea trout is a subspecies of brown trout and is found in Scotland as well as Iceland, Scandinavia and the Baltic.

Other trout species like the rainbow trout, steelhead trout, cutthroat trout, golden trout, golden rainbow trout, redband trout, and dolly varden trout, are all native to North America.

The photographs below will help you distinguish between some of the different trout species.

Brook Trout

You can see from the photograph below that the brook trout (which is a char) has a dark body and pale spots. Its dorsal fin also has a pattern on it, unlike the brown trout which has a spotted dorsal fin. It also has a white stripe on its lower fins. Brook trout are native to West Virginia.

Golden Trout

The golden trout is a small fish. It’s one of the smallest trout species. You can see from the photograph below that they have a gold coloured body with a red stripe running down its side. Golden trout are hard to find since they live in remote locations like rocky mountains.

Lake Trout

A lake trout is another char rather an a trout. You can see this from its dark body and pale spots. You will find lake trout living in the Great Lakes along with rainbow trout populations, and Atlantic salmon. Lake trout got their name because they are mainly found in large lakes in the northern United States.

Brown Trout

You can tell a brown trout from other any other type of trout due to its dark orange spots with pale halo. Its caudal fin (tail) is also dark brown with no spots.

Rainbow Trout

All rainbow trout have red stripes down their sides which help to distinguish them from other fish species. They are silvery and have many dark spots over their bodies.

Identifying Trout from the River Wandle

If you are fishing in the River Wandle, many of the brown trout here have a silvery colour and hardly any orange or brown at all. You can still identify them as brown trout however as they always have spots with a halo around them.

Since the brown trout in the Wandle have a silvery colour they are sometimes mistaken for rainbow trout. There are actually no rainbow trout in the River Wandle.

Rainbow trout were introduced to the UK from North America in the 20th century. Today the only self-sustaining population of wild rainbow trout in the UK is in the Derbyshire Wye.

Other Useful Articles

• A Guide to Fishing on the River Wandle
• Are there Pike in the River Wandle?
• What is a Fishing Leader?
• Do Trout Bite at Night?
• Do Trout Swim Upstream?

This post was about Brown Trout vs Rainbow Trout

Thank you for reading my post about brown trout vs rainbow trout. Both species of fish prefer to live in fast flowing, clear water. The biggest difference between them is their colouring and the markings on their bodies.