The first time I fished a Hexagenia mayfly hatch was entirely by accident. My brother Sam and I had pushed our boat up a small tributary stream that dumped into a large lake in northern New York State searching for post-spawn smallmouth bass. We’d figured that we could run up the creek for a few hours and then slowly drift back out to the lake, fishing as we went. However, the creek was shallow so we couldn’t use the engine, and it was dotted with fallen trees and snags along its length. It took a lot longer than we initially thought to paddle, pole, and shove our way upriver to the bridge where we planned to turn around and work our way back downstream.
By the time we started fishing it was getting dark, but with a full moon and a clear night sky we could still see well enough. It wasn’t until after a few unproductive hours fishing that I started to see the bugs. Great hordes of giant mayflies were drifting past us in the current and fluttering up from the surface of the water, landing on the boat, the trees, and on the brims of our hats. Then I heard the first splash.
What is a Hex Hatch? The name might make it sound like some sort of witch’s curse, but the Hex hatch is actually one of the most highly anticipated events in the world of angling. Every year in the late spring, the nymphs of the largest mayfly in North America, Hexagenia limbata, crawl and swim up from the muddy bottoms of the lakes and rivers where they live and crawl out onto the rocks and banks at the edges of the water. The bugs then shuck their skins, dry their wings, and prepare for one of the most wonderous displays in the animal kingdom. As the sun sets, literally thousands of the 2-inch-long mayflies will take flight, converging above the surface of the water to breed and eventually die in a kaleidoscope of whirling wings and dancing, bouncing bodies.
“It’s like the night has suddenly come alive during a hex hatch,” said former Orvis fly fishing instructor and guide Nathan Mackey, who fishes the hex hatch around the waters of Lake Champlain every year. “When it’s good, it’s like something out of a dream. The bugs will just materialize out of the dark, dancing around in the beam of your headlamp as far as you can see, crashing into the end of your rod tip, and completely covering your car and your boat. It’s absolutely nuts! Definitely an event you have to see to believe, and definitely an event you have to hit the water and fish.”
Every year, anglers flock to rivers and lakes across the country to experience the hatch, which typically occurs from late May to mid-June, depending on the weather. The bugs need water temperatures to reach around 60 degrees to hatch. They can appear in almost any body of water that has a muddy bottom for the nymphs to burrow into and grow. Hexagenia are the most widely distributed mayfly in the country and a hatch can happen almost anywhere, from as far west as Washington State to the East Coast in Maine, but the best and most consistent hatches usually happen in the waters between northern Wisconsin and eastern New York. These hatches can be sparse in some places with only a few bugs casually fluttering or drifting by an angler, or they can be so thick and intense that the swarms of insects are sometimes picked up on Doppler radar.
Occasionally, they even threaten human safety. I remember after one hex hatch I fished on the Connecticut River, the town had to hire snowplows to clean the bugs off the road along the river. There were so many dead mayflies in the street that they were causing cars to slide off the road.
Clearly, such immense hatches provide ample fishing opportunities for both fly and spin anglers alike–so long as you fish in the right spot, hit the water at the right time, and use the right equipment.
Equipment for Fishing a Hex Hatch One of the most unique things about the hex hatch is that it usually occurs in the late evening, and the best fishing happens at night. This vampiric habit of these bugs means that the delicate presentations and light lines you would normally have to use in other dry fly fishing situations can be cast aside. Instead, you should fish the hex hatch with the same heavy gear you would use during a stonefly or cicada hatch because both the low light and large size of the mayflies makes the fish feeding on them difficult to spook.
Another reason you’ll want to use heavier equipment during a hex hatch is because the number of bugs on the water makes fish competitive and aggressive and in certain waters. Almost every fish species in the ecosystem will move to capitalize on the banquet the bugs provide.
“It’s not just trout that come to the surface to eat hexes,” Mackey told MeatEater. “I’ve caught bass, trout, perch, and even weird things that normally don’t feed on the surface like walleye, pike, catfish, and even gar, all on hex pattens during the hatch. So, whenever I go out to fish it, I’ll use a much heavier rod and leader than I’d normally use to fish dry flies. Iit’s like Forrest Gump said: ‘You never know what you’re going to get.”
Even if the river or lake you’re fishing on only has trout, the standard 5-weight fly rod you normally use may still not suffice. Boosting up to a 6-weight or even a 7-weight during the hex hatch is a good idea because these big nocturnal bugs can bring trout to the surface of a size you may not see during any other time of the year.
“Getting into a bunch of 18-, 19-, or 20-inch fish every night is pretty standard during the hex hatch and that’s awesome,” fly fishing guide Westley Allen of Pere Marquette River Lodge said. “But what makes it truly special is the potential to hook into something that’s 30 inches or bigger.
“I’ve had times when I’m out on the river during the hatch and didn’t cast at a rising fish at first because the splash was so big I thought it was a beaver. I’m talking about those giant trout you know are out there because you rolled them once or twice on a mouse or a streamer, suddenly coming up to inhale your fly during the hex hatch. It’s really exciting.”
Accordingly, your leader and tippet should also be heavier than you would normally use in most dry fly fishing situations so you can handle whatever fish you hook into. Heavy leaders in the 0x to 2x range are standard for hex fishing, with tippet sizes of no smaller than 3x. Additionally, because you’ll be fishing in the dark, it may not be a bad idea to use a tippet ring to make tying knots a little easier and to string your reel with a glowing fly line so it’s easier to keep track of exactly where you’re casting and to monitor how your fly is drifting in the current.
The size of the Hexagenia mayfly and the aggression of the feeding fish means that spin anglers can also get in on the action with a light-action to medium-action rod. Use a reel strung with 6- to 10-pound-test monofilament or braided line, which is light enough to accurately cast small topwater lures but still strong enough to handle a big fish.
Best Flies and Lures for the Hex Hatch The hex hatch is such a well-known, widespread, and popular event among fly fisherman that almost every fly shop in the country will have at least a few different hex patterns somewhere in their store. Additionally, even if they don’t carry specific hex patterns, the insect’s large size and the fact that you’re fishing them at night when the fish can’t get a good look at them means there will still be several large attractor fly patterns that will work as well.
Standard hex patterns include the All Day Dun, the Ausable Parachute, and the Paradrake. If those are unavailable, you can also catch fish using basically any large yellow, tan, or white dry fly pattern. My favorites include the White Wulff and the Light Cahill in size 10 to size 6, as well as large yellow Stimulators and small Chubby Chernobyls.
While there are more intricate ways to fish these flies, depending on whether the bugs are emerging, mating, or just drifting along dead in the water, the general fishing method remains the same. Simply cast your fly upstream or at least in the general direction of where you hear or see feeding fish. Let it drift downstream at the same speed as the current. If the fly isn’t inhaled by a fish after a few seconds, give it a gentle twitch as it floats along on the water. Hexagenia are big mayflies and after hatching they often struggle for a few seconds on the surface before they take off. Gently twitching the fly can cause an otherwise disinterested or distant fish to move in and smash it.
Spin fisherman can do well using small floating lures with elongated profiles like the Fo5 Rapala and the Zara Spook. These lures can either be floated along the surface of the water or gently twitched to imitate a struggling mayfly or they can be cast and splashed down hard among heavily feeding fish. Usually, any active fish will hit the lure as soon as it lands on the water, causing you to set the hook so hard that you’ll send any smaller fish you hook flying into the trees behind you (or maybe that’s just me).
The hex hatch can be such an intense and rewarding fishing experience that many anglers who have fished it look forward to the arrival of the hexes more than any other time of the year.
“If I had to put down my fly rod for most of the season and could only pick it up for one month during the year, it would be when I think the hex may be hatching,” Allen said. “It’s just such an awesome time, sitting out there in the dark waiting for the bugs to arrive and knowing that when they do, something fantastic is about to happen. It’s just a very special time of year.”
The Night of The Hex The splash was massive. Then another strike happened, and another, until it seemed to my fevered brain like the sky was raining coconuts down into the water in front of us. Sam and I both clamored into the bow of the boat and started casting at every rising fish we saw, setting the hooks almost as soon as our flies and lures hit the water.
It was a night of rod bending, drag screaming, chaos. It was a night that most fisherman only dream about, where almost every cast one of us was netting a fat, struggling smallmouth or flopping a monster brook trout onto the deck—fish we hadn’t even known existed in the creek before that night. At the end, after we had drifted out onto the lake and were motoring back to the dock, feeling the hatching mayflies smack into our faces and staring aroundin awe as still more fish crashed around on the surface of the water, I knew one thing was certain—we would be back.