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Fly Fishing Using Terrestrials: Know the Bugs and How to Fish Them

One of the best things about summer fly fishing is the opportunity to fish terrestrials – that is, any fish food that comes from dry land. This includes bugs like grasshoppers, ants, beetles and crickets.

During the summer months, terrestrials can become a primary food source for trout. Many aquatic insects have already emerged and laid their eggs which leaves room for swarms of these high protein bugs. During this window, terrestrials are at their peak abundance. And trout will often take advantage of these calorie-rich meals.

As we enter peak terrestrial fishing season in Colorado, here are a few tips to keep in mind:


When and Where to Fish Terrestrials

The prime season for fishing terrestrials in Colorado is generally from late June through September, or whenever cold weather shuts down the land-based bug life. During this timeframe, terrestrials can make up the majority of a trout’s calorie intake in some waters.

When it comes to fishing terrestrials however, there are no hard and fast rules. In many cases, it’s as simple as paying attention to what you see on the ground. If it’s October and there are still grasshoppers bouncing around your feet – then by all means, tie on a hopper pattern.

Terrestrials will become available at ascending altitudes with the arrival of warm summer weather. While grasshoppers may be abundant on a lower elevation river in mid-June, it might be a few more weeks before they’re available at an alpine lake that’s 2,000 vertical feet higher.


Literally any water that holds trout can be an effective place to fish terrestrials. But like the answer to the “when” question, answering the “where” question is usually just common sense. Look for places where terrestrials might naturally fall in or be blown into the water.

Splash a hopper along a grassy cut bank. Drift an ant under overhanging brush. Or send a beetle pattern tumbling off a riffle and into a dark seam. During the summer, trout will be looking for opportunities to grab big, crunchy bugs. Wherever you see it, give them that opportunity.

Types of Terrestrials

Terrestrials can be split into three main groups (with perhaps a few outliers)…



First and perhaps most obviously are grasshoppers. Grasshoppers hatch as snow and cold weather makes way for summer. First you will see flightless grasshoppers called nymphs. While smaller, these hoppers still find their way into the water! Next the adults emerge with wings and especially when the wind blows they can get clumsy and find themselves meals for hungry trout.

Most anglers have probably taken the opportunity to fish a hopper at one time or another. Fishing big dry flies that are easy to see is just plain fun. Hopper patterns tend to float easily. Their buoyancy makes them perfect for supporting a dropper or two beneath the surface.

When fishing hoppers, a go-to tactic is to plop them down along the bank where a little splash will often entice a fish to strike. This can be deadly. But remember there’s more than one way to fish a hopper. Try skating a hopper through an area of slack water or twitch it along a foam line. You might even try adding a little bit of weight (a strike indicator can also be helpful) and sending a drowned hopper through a deeper run or below a cut bank. This can be especially effective on bright sunny days when it’s difficult to entice trout to the surface.




Beetles follow a similar cycle to grasshoppers and you may find more adults as the summer goes on. Beetle patterns might be some of the most underrated flies in any angler’s arsenal. Consider the fact that beetles are among the most prolific and widespread insects on the planet. They can be found anywhere in just about any size. And trout love them.

Beetle fly patterns can be fished in a variety of ways. Patterns like Grillos’ Hamburgler are tied with a highly visible parachute post, making them easy to fish as a single dry. On the other hand, small black beetle patterns that are difficult to see are often better fished behind another, more visible dry fly.

Beetle patterns can be fished almost anywhere on the water. While they might fall into the water along the banks, don’t limit yourself to these zones. A beetle can be quickly carried away, drowned, and become trout food anywhere in the river.

When we say that beetles are underrated, we mean it. When nothing else is working, a beetle pattern could turn your day around. Give it a shot and you might find one of your new favorite confidence flies.



Like beetles, ants are an available food source anywhere you find trout water. They come in a wide variety of sizes and colors. And like beetle patterns, some ant patterns are tied with a high-visibility parachute post, making them ideal for fishing as a single dry fly. However, fishing drowned ants in the surface film or beneath the surface can be equally as effective. In these cases, you can fish an ant as a dropper beneath a more visible dry fly or under a strike indicator.


If you plan on visiting any high alpine lakes in Colorado this summer, don’t go without flying ant patterns in your fly box. In the mid to late summer months, colonies will produce winged ants that swarm from the nest in search of new territories. When this happens, the flying ants can be blown across the water, sometimes by the hundreds. If you’ve ever experienced this phenomenon on an alpine lake, you know how special it can be. Even when there isn’t a swarm, keep flying ant patterns in your rotation on alpine lakes.


Miscellaneous Terrestrials

In addition to these three main terrestrial groups, you’ll find a few more patterns in the bins here at the fly shop. Other effective terrestrial patterns include Crickets, Crane Flies, Cicadas, and Yellow Jackets.

Contact Us With Questions

Check out our selection of terrestrial fly patterns here on the website and choose from free shipping or same-day curbside pick up. If you have questions or need help, please don’t hesitate to ask. You can visit us at the shop in Littleton or call us at 303-794-1104. Get out there and enjoy the terrestrial fishing season here in Colorado