How To Pick The Best Fly For Fly Fishing (Match The Hatch Guide)
Before you hit the water, check out these expert fly fishing tips so your day on the water is a successful one!
Quick Reference: Pick The Best Fly In 60 Seconds
- Match the hatch: pick a fly that looks like the insect currently flying over or crawling under the water where you are standing.
- Fish rising to the surface? Use a dry fly (floats on top).
- Fish not visible on top? Use a wet fly or a nymph (fishes below the surface).
- Big fish, no bugs? Try a streamer (imitates baitfish, crayfish, leeches).
- Rule of thumb by month (most of the US): March = nymphs (mayflies just hatching). June = adult Green Drake mayfly imitations for trout streams. Late summer = terrestrials (grasshoppers, beetles, ants).
- Check first: flip a rock in the shallows. Whatever swims out of it is what your fly should look like.
In fly fishing, many things matter: the form of your cast, the length of your rod, the weight of your line. Nothing matters more than the fly you tie on the end. Below is a plain-English guide to picking the right one, in the right water, at the right time of year, based on what the fish are actually eating.
If you are new to fly fishing, know that the fly is the bait, and it usually looks like an insect or larva. Compared with the bait used in conventional fishing, the fly is very light and glides across the water. A good fly imitates an insect’s natural behavior, which makes it more attractive to the fish.
Before You Hit The Water
Take Stock
Before you go anywhere, get familiar with the flies you already own. Open the box, sort by type (dry, wet, nymph, streamer, terrestrial), and note the gaps. That inventory tells you what you can fish today and what you need to buy or tie before your next trip. Skipping this step is why anglers show up with a box of size-14 mayfly imitations on a day when the fish are eating size-8 grasshoppers.
Select Your Catch
Knowing the fish you are trying to catch narrows the fly choice fast. Trout eat mayflies, caddis, stoneflies, and midges. Smallmouth bass eat crayfish, hellgrammites, and baitfish. Panfish eat almost any small insect. If you are on a trout stream, you are picking from one shelf of the box. If you are on a warmwater lake for smallmouth, you are picking from another.
Assess Water Conditions
Be a keen observer, especially of the water. Is the level high or low? Is it flowing slow or fast? Is it murky or clear? Each of these factors changes fish behavior and the fly you should pick.
- Clear, low water: fish are spooky. Go smaller (size 16 to 20) and use a longer, lighter leader.
- Stained or high water after rain: fish cannot see well. Go bigger (size 8 to 12), darker, and often below the surface with a nymph or streamer.
- Fast riffles: fish are looking up at food tumbling in the current. Buoyant, high-visibility dry flies work well.
- Slow pools: fish have time to inspect. Realistic patterns beat flashy ones.
Watch the weather too. Check the Farmers’ Almanac‘s fishing calendar, which rates the day’s fishing based on the phases of the Moon and other factors rather than your local conditions. Combine that rating with your on-the-water read for the best call.
Read: Do Phases of the Moon Affect Fishing Conditions?
Find Out What’s Hatching, When
Once you are on the water, the fly you use should look like the insects that are actually flying around. For example, during the month of June in most parts of the country, mayflies are in the midstage of their life cycle, compared with March, when they are just hatching. If it is June and you are heading to a trout stream, pick the fly that imitates an adult Green Drake mayfly (see above). Using other flies can still work, but is harder to predict. Your local fly-fishing outfitter can help. They will have specific information for your region.
A common phrase in the fly-fishing world is “Match The Hatch,” in other words, always match your flies to what is commonly hatching where you are fishing. Try this: head to your favorite stream, turn over a larger rock, and watch what signs of life are swimming around in terms of larva and insects. That is your best fly of the day.
Hatch Calendar (North America, Trout Streams)
This calendar is a rough guide. Exact windows shift with latitude, elevation, and water temperature. When in doubt, ask a local shop.
| Month | Common hatches | Best fly type | Sizes |
|---|---|---|---|
| March | Blue-Winged Olive, early stoneflies, midges | Nymph (below surface) | 16 to 20 |
| April | Blue-Winged Olive, Hendrickson, caddis | Nymph transitioning to dry | 12 to 18 |
| May | March Brown, sulphur, caddis | Dry fly | 12 to 16 |
| June | Green Drake, sulphur, caddis, stonefly | Dry fly (adult mayfly imitation) | 8 to 14 |
| July | Trico, caddis, terrestrials start | Dry fly, terrestrials in afternoon | 14 to 20 |
| August | Terrestrials (hoppers, ants, beetles), Trico | Terrestrial dry flies | 8 to 16 |
| September | Blue-Winged Olive returns, October caddis begins | Dry fly and streamer | 10 to 18 |
| October to November | Blue-Winged Olive, midges, spawning streamers | Streamer and small nymph | 4 to 20 |
| December to February | Midges only | Small nymph | 18 to 22 |
According to the U.S. Environmental Protection Agency, mayflies are one of the most-studied groups of freshwater indicator insects in North America. Their National Aquatic Resource Surveys track exactly the same bug groups your fly box is trying to imitate. If the science team is counting mayfly nymphs to grade water quality, the fish are eating them too.
Dry Flies Vs. Wet Flies: What’s The Difference?
There are two big families of flies you can use to catch fish: dry and wet.
Dry Flies
Used more often, dry flies imitate the adult stage of a flying insect that lands on the surface of the water and floats downstream. Fish see the fly hit the water and snap up the bait if it looks natural and appealing.
Terrestrial bugs (grasshoppers, beetles, and ants, which are normally found on land) sometimes fall in and float across the water, giving fish a tasty meal. Flies can be tied to look like those creatures too. Terrestrials come into their own from mid-July through September in most of North America.
Wet Flies
Wet flies fish below the surface of the water. They are designed to look like insects that have hatched and are on their way up (known as “nymphs” or “emergers”).
Another type of wet fly is a “streamer,” a larger fly designed to imitate baitfish, crayfish, and leeches, another meal fish enjoy. Streamers are the fly-fishing equivalent of conventional fishing lures. Big brown trout, smallmouth bass, and pike are common streamer targets.
Because wet flies work below the surface, some anglers use a “strike indicator” to help them see a bite. The simplest way to describe a strike indicator is that it is similar to a bobber in conventional fishing. Learn more about them here.
Time To Make The Cast
While trout and salmon are the top targets in fly fishing, other fish eat insects too: pike, bass, carp, and panfish. Every angler knows that sometimes you target one kind of fish and another species latches on. It is common for anglers to fish for trout and catch chub instead, because chub often share the same streams. If saltwater is closer to you, you can try casting for snook, redfish, bonefish, and striped bass.
Fly fishing is a meditative pastime for a lot of anglers. Understanding the nuances of the hobby makes your time on the water more fun and more relaxing. Do not be afraid to try different flies to see what the fish are looking for that day. Eventually, you will be skilled enough at recognizing different flies that you can start tying your own.
When To Change Your Fly (Field Rule Of Thumb)
Anglers who catch more fish switch flies more often than anglers who catch fewer fish. The plain rule most guides teach:
- Fish 15 to 20 good drifts with your current fly.
- If nothing looks at it, drop one size and try again.
- Still nothing, change color (light to dark or dark to light).
- Still nothing, change category (dry to nymph, or nymph to streamer).
- Watch the water for two minutes. Nothing hatching? The fish are probably not looking up. Fish subsurface.
Fly Tying: An Art Form
You can buy flies pre-tied at any fishing-gear shop or online. They are fairly inexpensive (typically $2 to $3 each), depending on where they were made and what they are made of. But fly tying is considered a relaxing art form and many people take up the hobby, even those who do not fly fish. Watch this fly-tying expert build a Green Drake mayfly, the same one mentioned above.
Best Fly For Fly Fishing FAQ
What is the single best fly for fly fishing if I only own one?
A size 14 or 16 bead-head Pheasant Tail Nymph. It looks like the immature stage of a mayfly, which covers a huge share of what trout, panfish, and even smallmouth bass eat across North America. It fishes below the surface, which is where fish spend most of their feeding time.
How do I match the hatch if I do not see anything hatching?
Flip a rock in the shallows. Whatever crawls or swims out is what the fish are eating right now, even if nothing is flying over the water. Size and color of the fly should match that bug within one hook size.
Dry fly or wet fly, which catches more fish?
Wet flies (nymphs and streamers) catch more fish on most days, because fish do 80 to 90 percent of their feeding below the surface. Dry flies catch more fish during a heavy insect hatch, when fish are actively rising. Choose based on what the water is telling you, not preference.
How often should I change flies?
If a fly has had 15 to 20 good drifts through likely water with no interest, change something. Drop one size first. If that fails, change color. If that fails, switch category (dry to nymph, or nymph to streamer). Guides who fish every day switch more often, not less.
Does the moon phase actually change fishing?
Yes, on measurable but modest terms. The Farmers’ Almanac fishing calendar rates each day based on moon phase and related factors. Anglers who fish “good” or “best” days over multiple seasons report higher catch rates. Weather and hatch timing still matter more on any given day.
What is the best fly for June trout fishing?
In most of North America, a size 8 to 12 Green Drake dry fly imitation, either during a live hatch or in the hour before dusk. Green Drake mayflies are one of the most geographically widespread mayflies on the continent and a documented trout favorite.
Should I tie my own flies or buy them?
Buy at first. Pre-tied flies cost $2 to $3 each. Start tying when you fish enough that lost flies add up, or when you want a specific size or color that shops do not stock for your local water. Fly tying is also a hobby in itself, one that many people enjoy even when they do not fish.
Larry Fleury
Larry Fleury is a writer and outdoor photographer who has a background in atmospheric science, marketing, astrophotography, creative writing, and all things outdoors. His photography has been featured by The Weather Channel, Midwest Living Magazine, and National Geographic Your Shot. Larry lives on the edge of the Ozark Mountain Range in Southeast Kansas, where he spends his free time fishing, camping, hunting, hiking, storm chasing, and playing guitar on the porch.
- Larry Fleury
- Larry Fleury
- Larry Fleury
- Larry Fleury
Here’s a nice brown trout I caught on a dry fly a few weeks ago.