The Starting Lineup – The 3 Flies You MUST Have for the Month of April

Spring is here, the rivers are waking up, and April marks one of the most dynamic months in the fly fishing calendar. As snowmelt begins to kick in and flows rise, the water temps climb just enough to get trout back into feeding mode. But it’s also a month that demands the right fly selection—and smart tactics—to find success.

We sat down with our veteran guide, Matt Weldon, to talk shop. With years of guiding experience across Colorado & Wyoming, Matt’s seen every shade of April water—from cold and clear to chocolate milk runoff. Here’s his “starting lineup” for flies he won’t leave home without this month, how he rigs ‘em, and how he fishes each one.

1. Zirdle Bug (Size 8–10)

The Big Ugly That Gets it Done

“April is Zirdle season. I don’t care if you’re fishing freestone, tailwater, or a side channel—this fly flat-out moves fish,” Matt says.

The Zirdle Bug walks the line between a streamer and a nymph, and that’s exactly why it works. It imitates a variety of protein-packed food like sculpins, crayfish, or even stoneflies. When trout are waking up from winter’s sluggish metabolism, they’re looking for calories. The Zirdle delivers.

Matt’s Tips on Fishing the Zirdle:

• Where to fish it: “Look for soft edges, slower banks, and inside seams. With runoff starting, that’s where trout are sliding into to get out of the heavy flow. I’ll also work tailouts and drop-offs where big fish ambush.”

• Rigging: “I like to lead with the Zirdle on a two-fly nymph rig. I’ll tie it on 3X or 4X fluorocarbon to protect against snags and give me confidence to pull hard. Below it, I’ll drop a small Baetis or midge off a 5X tippet.”

• Weighting: “Don’t be afraid to use a heavier split shot above your Zirdle if flows are up. You want this thing ticking bottom.”

2. Daysaver Baetis (Size 18–20)

The Go-To Bug for April Hatches

Named for its ability to produce fish when everything else fails, the Daysaver Baetis is a blue-winged olive pattern that has become a guide favorite—and one of Matt’s go-to confidence flies.

“Baetis are out in force this month, especially on cloudy or drizzly days. I can’t tell you how many days this fly has saved trips. Hence the name.”

Matt’s Tips on the Daysaver Baetis:

• Where to fish it: “Focus on riffle drop-offs, transitional water, and behind big rocks. Even with higher water, trout still slide into that knee-deep stuff where Baetis nymphs get knocked loose.”

• Rigging: “I usually run the Daysaver about 18 inches below a Zirdle or stonefly pattern. Keep it on 5X fluorocarbon to help it sink naturally. If I’m seeing mid-column movement, I’ll lighten my rig and fish it below a small tungsten bead jig style fly.”

• Presentation: “Keep your drifts clean. I’m talking no drag, especially in the soft water and eddies. Baetis are small, so if you’re not getting good drifts, picky fish will refuse it.”

3. Blindside Midge (Size 18–20)

Clean. Deadly. Dependable.

This is the sleeper fly of the bunch, but don’t overlook it.

“Midges are still a huge part of the diet in April, especially on the tailwaters or in slower sections of freestones. The Blindside by Jon Easdon is one of those flies that just produces in tough conditions,” Matt explains.

With its slim profile and subtle flash, the Blindside Midge doesn’t scream “look at me”—and that’s exactly the point. It matches those tiny, realistic midges that trout see all day long.

Matt’s Tips on the Blindside Midge:

• Where to fish it: “I’ll fish this fly behind the Baetis or solo below a Zirdle in deeper slow runs where midges are hatching.”

• Rigging: “This is usually my bottom fly. 4X or 5X tippet, depending on clarity. It’s small, so make sure it’s getting down.”

• Tactic: “If you’re seeing fish rise subtly and you’re not sure what they’re eating—try this. It works both as an emerger and a drowned adult.”

April can produce some BIG fish in our local waters!

How Matt Approaches April Water

April is a game of adjustment. Runoff hasn’t fully hit, but flows are rising. Visibility can go from gin-clear in the morning to muddy in the afternoon. Matt’s advice?

“Adapt and stay mobile. If water clarity drops below a foot, I go bigger and flashier with my lead fly—the Zirdle is perfect for this application. But if you’ve got 1-3 feet of visibility, you’re in business. I’ll spend most of my time working the edges, inside seams, and slow buckets. If you’re wading deep, you’re standing on fish.”

Matt’s also a big believer in giving each spot a solid 10–15 minutes, then moving on.

“April fish are spread out. They’re not all stacked up in one run like they are in winter. Cover water, adjust your depth and weight constantly, and don’t be afraid to lose flies.”

Meet Matt Weldon – Your Guide for April Success

Matt Weldon has been guiding full-time for over a decade and calls the Colorado, Eagle and Roaring Fork Rivers home. Whether you’re a seasoned angler or a total beginner, Matt’s calm, dialed-in approach and deep knowledge of local rivers and entomology make every day on the water full of education. His clients consistently praise not only his ability to find fish, but also his skill in breaking down the “why” behind every move.

Want to fish with Matt this spring? Give us a call at 970-236-1937 to reserve your guided trip!

Whether you’re chasing your first trout or looking to master spring runoff tactics, Matt’s the guide you want in your corner.

Tight lines and happy fishing—see you on the water.

-The CRO Team