Ask MidCurrent: How Do You Fish Caddis-Pupa Imitations?

Question: How do you fish caddis-pupa imitations? Just like a regular nymph?
—Nick, St. Louis, MO (via the Ask MidCurrent form)

Answer: Spring brings prolific caddisfly hatches on many trout rivers, and trout often feed heavily on the pupa stage. Unlike mayflies, adult caddisflies don’t linger on the water—they fly off almost immediately—so trout get most of their calories before and during the emergence, when pupae drift and struggle upward in the water column. In fact, caddis pupae can drift for hours (even miles) before finding the ideal temperature (50–55°F) to hatch. This makes pupae easy targets for trout over an extended period. As a result, fishing pupa imitations is often the most effective way to catch trout during a caddis hatch, especially in spring, when famous events like the Mother’s Day caddis blanket rivers in April and May.

Hatches typically kick off in the afternoon as the water warms and can last until dusk, but trout may start feeding on drifting pupae by late morning. Wise anglers will “match the hatch” before it’s obvious: imitate the subsurface pupae early, then switch to dries only once trout consistently hit adults on top.

Reading Water and Trout Behavior

Target riffles and runs: Caddis emergences usually occur in riffly, oxygenated water. Trout will congregate in these riffles during spring hatches to gorge on drifting pupae. Focus on the heads of pools, tailouts of riffles, and seams. Early in a hatch, the best action is often just below riffles where pupae are thickest. If spring flows are high or slightly off-color, look to the softer edges and side channels; big trout often move out of heavy currents into side pockets where fewer naturals mean your fly is more noticeable. Using a stream thermometer helps to time things: caddis pupae start drifting as water nears 50°F and emerge around 55°F.

Observe trout behavior: Trout eating caddisflies often porpoise or even break the surface to snatch emerging pupae or adults. If you see trout “torpedoing”—bulging the surface but not visibly taking dries—they’re likely nailing pupae ascending just below the film. If few adults are visible but fish are active, tie on a pupa imitation. That ssaid, during “blanket” hatches, trout may prefer the easier meal of helpless pupae over the winged adults dancing above. Recognizing these clues will tell you when to fish your caddis pupa imitation at depth, when to present it near the surface, and when to switch to (or add) a dry.

Presentation Techniques and Depth Control

When you’re fishing caddis-pupa patterns, presentation can make all the difference. The goal is to mimic the natural behavior of pupae in spring: drifting, then rising and pulsing toward the surface. Here’s how to fish your way through the mergence:

High-sticking is a great way to fish in the morning, as it gets your flies down near the stream bottom. Photos: Charles Hildick-Smith

Dead-Drift: Start by presenting the pupa on a drag-free drift. Whether it’s suspended under an indicator or a dry, ensure that your fly is drifting naturally with the current. In early hatch stages, keep the drift deep, bouncing just above the streambed where freshly emerged pupae are initially drifting. As the hatch progresses, trout will move up in the water column, so adjust by shortening your dropper or indicator depth to drift the pupa higher.

Swing & Lift: One of the most effective presentations is to let the fly swing upward at the end of the drift. Just as your line straightens below you, that pupa imitation will accelerate and rise, just like a natural pupa rising to emerge. You can simply let the current pull your line tight, or intentionally cause the fly to rise: as your fly drifts toward the end of the swing, slowly raise your rod tip or tighten the line to make the fly ascend. This often draws savage strikes. In fact, many strikes occur on the swing or just as you begin to lift, so always finish each drift with the fly rising and be ready.

Subtle Movement: While a dead drift is usually the starting point, caddis naturals are quite active. If you’re not getting strikes, try imparting slight action during the drift. For example, a very gentle twitch of the line or rod tip mid-drift can make your pupa flutter a bit. Gary LaFontaine recommended a technique he called the “stutter” – holding some slack line and feeding it in short pulses – to animate drifting caddis pupae. You can also experiment with short strips or wiggles as the fly drifts. This is especially useful when fish are actively chasing food (e.g. you notice trout moving side-to-side or up/down in the water column).
The Right Depth: Continuously read the water and adjust your rig’s depth. In spring, early mornings might find trout hugging bottom, so add weight and lengthen your leader. As the sun warms the water, insects get active higher up in the water column, you should shorten up accordingly. During a hatch, you might start the day fishing a heavy pupa near the substrate, then by afternoon be presenting an unweighted emerger just under the surface.

Pupa Patterns for Spring

Having the right fly pattern will greatly improve your success. Trout can be selective during dense hatches, so it pays to carry a variety of caddis-pupa imitations in different sizes, colors, and weights. Here are some proven patterns highly recommended for spring caddis activity:

Gary LaFontaine’s Deep Sparkle Pupa (left) and Emergent Sparkle Pupa mimic the air bubble that the naturals use to rise in the water column. Photos: Umpqua

LaFontaine’s Sparkle Pupa (Deep and Emergent variants)
The Deep Sparkle Pupa (usually tied with a bead or weight) imitates a caddis pupa drifting near the bottom, with a shimmering gas-bubble sheath, while the Emergent Sparkle Pupa (unweighted, with an Antron shuck) mimics a pupa rising to the surface. Carry them in olive, tan, and brown in sizes 14–18.

The Caddis Poopah works great as the lead fly in a two-nymph rig. Photo: Umpqua

Fox’s Caddis Poopah
Developed on California’s Lower Sacramento River by Tim Fox, the Poopah has a slender, sparkly body and soft-hackle legs. It’s typically tied with some weight (beadhead or wire) and is deadly in the drift or swing. A Poopah in cinnamon, tan, or olive, in sizes 14–16, is an early-spring staple on many Western rivers.

The Iris Caddis is known as a fly that takes wary trout when other patterns fail. Photo: Umpqua

Iris Caddis Emerger
Developed by Craig Mathews of Blue Ribbon Flies, the Iris Caddis is a killer surface emerger pattern. With a shuck of Zelon and a sparse wing, it’s designed to sit in the film as a stuck emerging caddis. It’s especially effective during spring evenings when trout are sipping just under the surface. Carry it in olive, tan, and gray sizes 14–18.

Soft Hackle patterns, such as this green Sparkle Soft Hackle Caddis, offer lots of lifelike motion in the water. Photo: Fulling Mill

Soft-Hackle Caddis
Traditional soft-hackle wet flies are superb caddis-emerger imitators. Patterns like a Partridge and Green, Partridge and Orange (for brown/tan caddis), or a simple Brown Hackle Peacock in sizes 12–16 work wonders. Swing them in riffles or fish them as a dropper behind a dry or a nymph.