Gearing Up For The Hex Hatch

by Dave Leonhard

The big bugs are nearly here. Sulfurs (both of the tiny pale yellow mayflies ephemerella invarias #16 and ephemerella dorotheas #18), yellow stoneflies #12-14, brown drakes #10, isonychia bicolor #10, and of course, the hexagenia limbata (hex #4-6). It doesn’t matter that you know the Latin names of the insects that will be hatching over the next several weeks, but it will certainly matter that you match the size, shape, and color of them with your flies to fool the feeding fish. Size does matter.

This hex (hexagenia limbata #4 dun) requires a 3X tippet and will be the last to emerge from silt beds at dark around 11pm late June evenings.


Here’s where it gets tough. The evening fishing begins with size #16 and #18 sulfurs. Tiny yellow mayflies that require fine, hair-like 6X tippets. So, from 8-9:30pm you need a very fine leader. Then around 9 or 10pm, the brown drakes or isonychia bicolor show up and are a size #10. Those larger flies require a heavier tippet to properly turn them over. Most would use a 4X or 5X tippet for those flies. Then,… as if it wasn’t tough enough,… the size #4 hex insects show up around 10:30pm or 11pm at dark, and they need a 3X tippet to turn them over. At this point it sounds like you’re going to be tying tippet and leaders all night. But relax. That’s why we’re here.

You only need to gear up properly. Before you get into the river, prepare. Start by putting on a 7 ½  foot, 3X leader. Then, tie on one foot of 4X tippet. Now tie on a foot of 5X tippet to the 4X section. And finally, tie on a piece of 6X tippet to your 5X and you’re ready to fish your 10 ½ foot 6X leader.

This sulfur (ephemerella invaria #16) requires a 6X tippet and will be the first of the insects in the late June evenings around 8pm.

Since the sulfurs are the first to emerge or spin, you can tie one onto the 6X tippet. When you see the first of the larger iso’s or brown drakes, you can cut off the the 6X tippet back to the 5X or 4X and tie on an iso or brown drake pattern. If the iso’s or drakes don’t show up and instead, yellow stoneflies are in the air, only cut back to the 5X.

Eventually, Hex size #4 will arrive… we hope… and you’ll need to cut off all of the tippet you tied on before entering the river and tie on your fly to the original 7 ½ 3X leader. Now you’re ready to go.

This isonychia bicolor spinner size #10 displays the white rear two sets of legs that is responsible for it's common name "White-Gloved Howdy".

Keep your little aquarium net handy to capture the bugs as they float by so you can properly examine them and match the proper fly to the bug. Keeping them in a small vile makes it easier to examine them more than once. Watch the air to see if night hawks or swallows are flying over the river eating insects. Since the first of the bugs are very small, it may be difficult to see the insects on the water, especially small #18 sulfur spinners. It’s sometimes necessary to wade over to a slot (flow of water running against a log… look for foam lines coming off the end of the log) and put your small bug net in the surface water where the foam is collecting and see what collects in your net.

Remember your headlight, and perhaps a backup. Put your bug dope on before you get into the river. Clean you hands so you don't dissolve the coating on your fly line with the DEET. If you don't want to turn your flashlight on while fishing (large brown trout are especially light-shy) you might want to put tippet on the large hex flies you will fish in the dark and tie a large perfection loop in the end so you can tie a perfection loop in your leader and just loop to loop you flies on in the dark without looking.  Then, just hang them on yo vest or sling.

Once you're in the river (about 7:30pm) and ready to fish, relax. Find a section with some cover such as log jams or a deep bend where large fish will seek safety during the daylight hours. Preferrably this water will be slow moving and flat or quiet water where you can hear rising fish. Take time to watch the water. Note where the obstructions and debris might be while it is light so that you don't get hung up in the dark. Most likely you'll see small fish feed on the dorotheas (#18 sulfur mayfly). Watch the sky. If you see birds lining up along the river in the tree tops, then you'll know that they too expect a good hatch. Once you see them flying over the river, you can anticipate some better action.

Around 9pm you may see some larger mayflies. We have discussed how to change flies and tip down to the appropriate diameter tippet size. The larger fish will become more agressive and move further out of the log jams as the light gets lower. Be quiet and listen for larger fish feeding. When you hear or see where a large fish is feeding, move quietly and carefully into position. A good position is slightly upstream of the feeding fish. Be patient to wait for another feed and confirm that you're in the right position. When you are ready to cast, cast upstream of where the fish fed. Remember that they have to rise up the the insect and float downstream as they rise. They then return to their comfortable, safe holding position. Start upstream and short of your target and work each successive cast closer to where you think the fish will feed again. If it is very dark and you're not sure how far away the fish is feeding, you can cast twice, and without changing the length of your line, move your feet 6 inches closer each successive couple of casts until you're right on target.

Now that you're ready to catch lots of large trout during the hex hatch, please remember to return the fish carefully. There are only a few large fish to go around, so be careful with them. For more on this subject, please read: The Silent Hatch .  

For more information regarding these hatches, flies, or leader selection, you can call our store (231) 933-9300 or refer to Forum article "How to Choose the Right Leader".