Are Trout Carnivores? Defining The Opportunistic Eater

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Stonefly and Mayfly nymphs crawling underneath a stream-bottom rock in Wisconsin.

Understanding a trout’s diet is vital to successful fishing. One common question from first-time trout anglers is, “Are trout carnivores?” 

Trout are carnivores with a bug, baitfish, and crustacean-heavy diet. But there are minor exceptions to this rule. 

Are Trout Carnivores or Omnivores? 

With a diet full of insects and baitfish, trout are carnivores. However, they are opportunistic eaters that will swallow anything edible carried downstream. 

For example, as fry, trout will feed on phytoplankton and zooplankton. As these trout grow, they target larger organisms, such as invertebrates, crustaceans, and other fish.

Since hatchery trout eat pellets, which can contain plant-based ingredients, one might think they are omnivores. But the pellets they use match a fish’s wild diet. In trout’s case, their pellets are high in protein and salmon fry.

One exception to the trout-carnivore rule is stocked trout. Upon release in the wild, hatchery fish have a naive diet and bite corn or PowerBait. So, although they prefer a carnivorous diet, some trout are susceptible to omnivorous habits. 

Trout Diet 

Aquatic and non-aquatic insects make up the majority of a trout’s diet. 

Aquatic Insects 

Aquatic insects are water-borne bugs that hatch into winged, air-breathing adults. These flies spend most of their time underwater and undergo complete or incomplete metamorphosis. Common aquatic insects include mayflies, stoneflies, and caddisflies.

Before hatching into adults, each fly undergoes several stages as an egg, larva, pupa, or nymph. Most fishermen clump these terms and call subsurface bugs “nymphs.” So, although specific lifecycle stages are helpful to fly fishermen, they are seldom necessary.

To find a nymph, grab a rock from the stream bottom, flip it over, and you will see nymphs crawling everywhere. Consider this the beginning of your entomology education.

From behind the counter at a local fly shop, I’ve heard some old-timers estimate that 90% of a trout’s meals are aquatic flies. And in my experience, nymphing is the most effective way to catch a ton of trout. 

Non-Aquatic Insects 

Non-aquatic insects, often referred to as terrestrials, are land-born bugs. Popular examples of bugs used for trout fishing include grasshoppers, crickets, ants, and beetles. 

Try fishing with terrestrials in the late summer because they elicit aggressive bites from lingering trout. Smack your foam hopper or cricket on the water, and prepare for an airborne brown, brookie, or ‘bow to take your fly. In my opinion, a trout exploding on a terrestrial is the epitome of fly fishing. 

Consider a dry-dropper technique if you’re unsure if trout are eating nymphs or dry flies. A dry-dropper is the best of both worlds and uses a nymph tied below a dry fly—usually, a terrestrial.


Trout prefer to trade numbers for size when possible. This means forgoing a low-caloric bug and chasing baitfish, leeches, crayfish, and worms. 

These meals might be less prevalent than nymphs, but their high-calorie intake is worth the squeeze. Large trout, especially brown trout, leave their lairs each night to prey on baitfish, crayfish, sculpins, and even mice. 

When fishing, an angler casting bait or streamers may catch fewer fish than someone nymphing. But in my experience, the average size catch is substantially larger

David, with a big female brown trout caught on a black streamer. This 20-inch brown was caught during the late winter in Wisconsin.
David, with a big female brown trout caught on a black streamer. This 20-inch brown was caught during the late winter in Wisconsin


Trout will also eat their own kind when given a chance, even when trout are eggs. This is most prevalent during the spawn if eggs are left unguarded or carried downstream.

Like nymphs, anglers can fish an egg pattern by letting it drift or float downstream. The egg will be effective if your line lacks drag and has a natural drift. 

Related Questions

Are Rainbow Trout Carnivores or Omnivores? 

Typically rainbow trout are carnivores, but stocked trout are omnivorous. Anglers can catch stockers on corn and PowerBait, but these presentations are unnatural and seldom available to rainbow trout.

Are Brown Trout Carnivores or Omnivores? 

Brown trout are carnivores and serious predators. Even in small streams, I know of brown trout over 25 inches, which is a credit to their high-protein diet. 

Why Is Trout Meat Pink? 

A trout’s meat color is a reflection of its diet. Trout with pink flesh have a high-carotene diet from consuming crustaceans. Farm-raised trout can develop pink flesh because hatcheries infuse their pellets with carotene. 

Do Trout Eat Mosquitos? 

If available, trout will eat mosquitos in every stage of their life. But don’t expect to hear anglers bragging about their latest homemade mosquito pattern tied on a vice. Instead, a more popular fly pattern resembling mosquitoes is a midge.

Do Trout Eat Mice? 

They sure do, especially giant trout! Mouse patterns are popular for fishing at night and excite wise trout. If you want to catch the trout of a lifetime, consider fishing a mouse. 

Catch Alaska trout with a mouse fly!

Final Thoughts 

Trout are carnivores that eat baitfish, crayfish, terrestrials, and aquatic insects. This robust diet creates a range of lures for trout anglers. 

In my experience, it’s better to be safe than sorry when preparing for the water. So Merry Christmas, it’s time to buy every lure or fly on the shelf!

David Linsmeyer Avatar


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