When it comes to fly fishing, trout is probably the first fish people think about. And this is for a very good reason — trout can be found in most streams and rivers in most areas along the North Pacific coast and have been introduced to Europe and even parts of Asia.
Trout are smart, sneaky, and hard to catch. They are simply great fishing.
There are many types of trout. They have a dazzling variety of sub-species and, as a result, can be tricky to identify — especially throughout the different phases of their lifecycle.
So, if you are having trouble figuring out exactly what kind of trout you have locally, or even what to expect on your next fly fishing trip, no worries, we’ve got your back.
To help you along, we’ve created a comprehensive guide to understanding the wide variety of beautiful fish that the Trout family encompasses and recognizing just what makes each sub-species different.
The first step in understanding trout is to see how it differs from salmon. Once we have cleared that up, we’ll go into all the ways in which the many sub-species of trout differ from each other.
WANT OUR BOOK? THE COMPLETE BEGINNER GUIDE TO FLY FISHING GEAR DOWNLOAD FREE NOW!
For more information on trout and how they can be caught, check out some of the best fly fishing books in our breakdown.
Explaining Trout Species
Trout, like their close cousins salmon, are part of the salmonid family of fish.
Because trout are closely related to Salmon, the two share many characteristics, and it takes a bit of knowledge to differentiate them. It doesn’t help that they come in so many varieties — cutthroat, tiger trout, golden trout, brown trout, brook trout, bull trout, rainbow trout, arctic char, and dolly varden, just to name a few, and that’s just scratching the surface.
While trout are genetically capable of spawning together or interbreeding to produce offspring, most species have remained distinct for centuries. The main reason they have managed to remain distinct is how each trout species adapts to their environment and different breeding habits. Different trout species have different spawning times and locations, making it difficult for different varieties to mate. Also, each trout species or subspecies have different feeding habits — larger trout feed on other fish while small trout eat insects and other small water animals.
See also our full post on What Do Trout Eat here.
The ability to identify the type of trout (or any other species) you catch is an essential skill every angler should have. It can be challenging for stream anglers to identify the different fish varieties around, especially in an unfamiliar area, but bear with us. We will explore the different types of trout species and how they can be identified.
Identifying Trout vs Salmon
Salmon and trout closely resemble each other, especially during the smolt state. During this stage, salmon (called the parr) lose their camouflage bars, and their bodies go through changes to help them survive the shift from freshwater to saltwater. Salmon spend most of their time in brackish rivers, adjusting to saltwater to grow to adulthood. Most trout, except for coastal cutthroat trout and Steelhead trout, stay in fresher waters.
At this stage, color is not a reliable characteristic for telling trout and salmon apart. But it is essential to be able to tell the difference because regulations are species-specific, and what is appropriate for one species may not apply to the other. Here is a guide to help anglers differentiate between trout and salmon.
Trout and Salmon Locations and Habitats
Location may help you tell the two apart, but it’s not really definitive. Pacific Salmon are indigenous to the North Pacific regions, as are many species of trout, especially the rainbow trout and coastal cutthroat. The Atlantic is a different story. While there is a variety of Atlantic salmon, it is more closely related to trout than their Pacific Salmon brothers.
Atlantic salmon and trout can be considered the “original” species. These can be found primarily in the Atlantic but have migrated to regions in the Baltic and other parts of Europe.
Both trout and salmon are found in freshwater and marine ecosystems and are popular among commercial and recreational fishers.
Are trout bigger than salmon?
As anyone who has seen a rainbow trout knows, trout have round heads and thick bodies, but salmon are generally bigger. Salmon, on the other hand, have adopted more pointed heads with slender, streamlined shapes. Additionally, salmon are usually heavier, and they can weigh as much as 103 pounds. Trout weighs 2.2-60 pounds and measure 16-55 inches in length.
What has a bigger mouth and tail, trout or Salmon?
Salmon have relatively small mouths, which barely stretch beyond the point under the eye, while trout have large mouths that extend beyond the line that you can draw beneath the eyes. When it comes to the tail, trout have broader, curved tails while salmon have more slender, forked tails. Also, the tails of trout are more slippery than those of salmon. You can tell this by the ease with which you can pick up a salmon by the tail. A trout will just slip away.
Do salmon and trout have the same teeth?
The most apparent difference between the two fish species is in the head and tail areas.
Both Trout and Salmon have vomerine teeth. These are teeth designed to grab on to prey and not let it escape. They grow on the roof of the jaw. Salmon have small vomerine teeth arranged in one row on the jaw itself and very few on the central line of teeth that extends over the middle of the tongue.
On the trout, the vomerine teeth are in two rows. One row is along the jaw itself, and one row is along the vomerine head or central line. They are arranged in a zig-zag pattern. By taking a look at how many rows of teeth the fish has is the easiest way to tell if your catch is legal where restrictions apply.
Do trout and salmon have different spots?
Sea trout usually have a lot of black spots located above and below the lateral lines. Salmon have fewer spots, and those they do have are only found above the lateral lines. If you see a fish with many spots that go beneath the midline towards the belly, it is most probably a trout. There is also a species called a specked sea trout.
Do salmon and trout reproduce differently?
Trout and salmon both live in freshwater during the early stages of their lives and migrate to the sea where they reproduce. Sea trout tend to migrate to the streams during the spawning season and return to the sea after this season. Females produce more than 2,000 eggs during this season.
On the other hand, Salmon stay in the sea for 1-5 years before they are ready for spawning. Unlike trout, some species of salmon spend their entire lives in lakes and rivers while the migratory species travel up to 900 miles to find suitable breeding areas. Salmon females lay more than 5,000 eggs during this season. Sadly, after the hard work of the spawning season is completed, salmon die.
Do trout taste better than salmon?
Unlike trout, salmon are rich in vitamin D and Omega-3 fatty acids. Trout contains fewer calories, protein and fat, and have yet to reach the popularity of salmon. As such, salmon are extensively cultivated in aquaculture projects around the world. Salmon is a staple in many world cuisines from Norway to Japan and is eaten in many ways, from heavily smoked to enjoyed raw.
What lives longer, salmon or trout?
Trout can live for up to 20 years, while salmon usually only survive for up to 13 years.
Types of Trout Species
In addition to trout pictures, other methods can help anglers who want to identify the various types. Weight, habitat, the presence or absence of spots, coloration, fin size, skin texture and slipperiness, teeth arrangement, and many more factors can contribute to the easy identification of different species of trout.
Here are the most common species of trout and everything that makes them unique:
It is also called the speckled trout and is the most beautiful of the trout species. Brook trout images show that their lower fins have white leading edges that are backed by black before fading to a reddish tint. They also have yellow spots on their backs, which extend to form worm-like shapes. On the sides, the brook trout’s color changes from olive to orange or red with scattered spots that make it almost similar to the red trout. Unlike the red trout, the brook trout measures 9-10 inches in length.
See our post, World Record Brook Trout, if you want to know the biggest brook trout ever caught!
In North America, the spawning season for Brook Trout is from September to November. Brook Trout are promiscuous, and male and female fish will mate with multiple partners throughout the season. It takes about 100 days for the relatively large eggs to hatch. The sensitive larvae will hide in the gravel until they’ve exhausted all of the nutrients from the yolk sac, and only then will start their adventure.
They are easy to catch, and their numbers reduce drastically due to excessive trout fishing activities or the changes in their environments. Most brook trout in North America can be found throughout Canada and inhabit the northeastern regions of the United States, Western Minnesota, and the southern side of the Appalachian mountains of North Carolina.
Brook trout are rare as they are found primarily in remote headwater streams. They prefer wading through the clean, cold mountain streams like the Chesapeake Bay watershed and are most active in the early morning hours and at dusk. Anglers looking to catch brook trout during the day may need to explore the deeper waters.
Brook trout feed on the adult and the nymph forms of insects, ants, and beetles, and small fish when available.
Brown trout, introduced to North America from Europe, vary greatly, depending on their habitat; there is the sea trout, small resident trout, and lake brown trout. It is difficult to distinguish between the small resident trout and those preparing to leave their birthplace for the sea. The only real way to tell is that the small resident trout have developed sexual organs while fingerlings do not.
Brown trout images show that those living in the sea have a silver color and dark back. The sides and covers of the gill have lots of black spots and a lateral line above and below. Those living in lakes are also silver, though they have a brownish shade with spots surrounded by paler halos.
When spawning, the brown trout in North America prefer breeding in small streams and rivers. They leave the lake or sea and swim up their native river. The small resident brown trout, however, spends its entire life in the stream and does not need to migrate during the spawning season.
Brown trout feed on small invertebrates that live at the bottom of the sea and plankton. The lake brown feeds on smelts, whitefish, bleak, and other aquatic species. They occasionally move to rivers to look for surface insects and larvae.
Brown trout live in freshwater near oceans. They require clean, cold, and well-oxygenated water in rivers and large lakes. As a result, you are likely to find brown trout in Finland.
According to most rainbow trout pictures, the species’ appearance closely resembles that of the salmon, though its shape and color vary based on age, habitat, and sex. The back of the rainbow trout takes on different colors based on the time of the year. For example, the reds, yellows, greens, and violets appear bolder. The rest of the body has dark spots on the upper part above the lateral lines and on the upper fins, while the lower side has a silver color that fades into a white shade beneath.
Rainbow trout are carnivores, eating aquatic insects, and other fish, such as the salamander and crayfish. They also feed on stoneflies, mayflies, nymphs, pupae, algae, and small mollusks. This dietary preference is what makes them so popular for fly fishing. Rainbow trout are known to cover vast miles upstream to look for food.
Rainbow trout live in the Northern hemisphere’s cold waters but have also been found in the Pacific Ocean, the Pacific Coast of North America, and the eastern coast of Asia. They do not thrive well in lakes where most anadromous fish stay.
There are two types of rainbow trout – the steelhead (partly lives in the river and partly in the sea) and the freshwater rainbow trout.
Rainbow trout mature at the age of 3-5 years, making their reproductive organs develop faster than any other kind of trout. They reproduce during early spring or late winter when the temperatures rise. The adult female rainbow trout migrates to shallow streams with clear water to spawn.
This season lasts up to five months (late March to early July) based on the winter conditions and the location where rainbow trout produces 200-8,000 eggs. Hatching may take up to four months, which is based on the water temperature.
Cutthroat trout have distinctive orange marks on the undersides towards the lower folding of the gill plate area. These unique cuts give them the name cutthroat trout, as the orange line under their throat looks like a cut. Their colors vary from one species to another. However, most cutthroat trout are recognized by their distinctive spots. Some cutthroat trout have yellow spots while others have red ones.
Unlike the cutthroat trout, the lake trout inhabits larger water bodies, and it is the largest of the trout species. It has a green, dark purple, or silver color based on its habitat, and its flesh can be white or orange, depending on its diet. Smaller lake trout have a red-orange flesh due to the high concentration of insects, flies, and crustaceans in their food.
Lake trout mainly pursue large prey, including other trout types, so if you are going for lake trout fishing, carry large lures or bait. Whitefish, ciscoes, and graylings are a great source of food for this wild trout.
Golden trout are one of the smallest of the trout family. Just as their name suggests, they are golden with red-orange stripes on the side. Also, the rear just before the tail of the golden trout is spotted with dark marks. Golden trout live in high-altitude freshwater rivers and lakes located in the mountainous regions.
Like many other trout feed on surface insects, small crustaceans like the freshwater shrimp and terrestrial insects. Due to the scarcity of insects during winter, golden trout have a specific feeding season, which begins in May and ends in September.
If you are interested in fly fishing, this is the best time to catch them. Golden trout also live in freshwater bodies in the western regions of the United States. They are most common in Washington, California, Idaho, and Wyoming.
Trout Identification Chart
While it isn’t always easy to tell the difference between types of trout, this brief guide should help you have a better idea of what you are likely to catch when you are fly fishing.
Don’t rely only on pictures alone when you are trying to distinguish the different species. A trout’s colors, location of its spots, adaptations, habitat, and other unique features should help you determine what type of trout you are dealing with and figure out what fly fishing techniques to employ.