The short answer is yes — you can fish nymphs during a hatch and it does work. In fact, even when the sky is dark with clouds of October Caddis or March Browns, there are times when nymphs out-fish dry flies.
Match the Entire Hatch — Not Just Emergence
A “hatch” is usually thought of as the period when insects emerge from the water to become winged adults. That’s why fishing a dry fly is typically the go-to strategy when a hatch is popping off. But there’s a lot more to an insect hatch than what you see above the surface and nymphs give you access to it all.
Looking for Pre-Hatch Clues
Most species of aquatic insects spend around one year underwater as nymphs, going through a larval and pupal stage before they emerge as winged adults, reproduce then die. Before the insects fully hatch, there’s a time period — anywhere from one hour to several days depending on the species — of increased activity. The extra crawling and scurrying around results in many nymphs getting dislodged and drifting downstream — a perfect feeding opportunity for trout.
But here’s where things can get confusing…
Not all nymphs hatch at the exact same time, which means that there may be some nymphs still in the pre-hatch phase while others have fully emerged and hatched. If you’re getting skunked fishing dry flies in a situation like this, it could be that the trout are keying into the drifting nymphs that are either more abundant or easier targets.
Switch to a nymph rig — traditional, indicator, or Euro Nymphing — and see what happens.
The False Emergence Illusion
There are times when trout appear to be rising when there doesn’t seem to be anything on the surface for them to eat. When that happens, there are two things the trout might be doing: eating emerging insects trapped in the surface film or eating nymphs that are “false” or “bluff” emerging.
Luckily, both instances can be remedied by fishing nymphs, particularly the “false” emergence.
Certain species of nymphs, namely Baetis and other swimmer mayflies, may make a few runs to the surface and back down before they’re fully prepared to emerge. This action can be mimicked a few different ways, but perhaps the most effective is by using a traditional nymph rig with a standard tapered leader and no indicator. Since the false emerging nymphs will be somewhere between the surface and the middle of the water column, using unweighted flies without additional split shot — just like you would a dry fly — should put your flies right where you want them.
Fishing Emerger Nymph Patterns During the Heat of the Hatch
Trout are all about easy meals, and emerging insects provide just that. Unlike their graceful nature in the air, insects during emergence are clumsy, frantic creatures. Not only do they have to wriggle themselves free from their larval or pupal shells, they must break through the surface tension to enter the atmosphere. This process can last from a few seconds to over a minute during which time an opportunistic trout can amble over and get a bite to eat.
There are many ways to rig and fish emerging nymph flies during a hatch, but here are two great options to help you get started:
- Tandem nymph rig with or without a strike indicator: Tie your nymph rig as you normally would and position your emerger fly pattern in the upper position so that it rides higher in the water column. Use the larval or pupa version of the same fly in the lower position and add split shot or weighted putty to adjust for the depth of the river accordingly. Use a strike indicator if you can get away with it, but if the water is clear you may need to go without and fish tight-line.
- Dry-dropper rig: We’ll cover this highly effective way to fish nymphs in a separate article (chapter) but keep it in mind when you want to fish emerger nymphs. In essence, you’re using a buoyant dry fly as a strike indicator, fishing an emerger fly just below. Since you’re imitating both the winged adult and the emerging nymph, you get the best of both worlds!
When in Doubt, Fish a Nymph
Keep these strategies for fishing nymphs during a hatch in mind next time the bugs are everywhere but your dry flies aren’t producing. Don’t forget that although there might be action happening on the surface, what’s happening underwater might be more interesting to the trout you’re after.