Best Flies For Spring (and Why): Midges, Mayflies, Eggs, and Worms

As temperatures rise across the nation, the aquatic world comes alive. Warmer weather triggers the natural cycle of insect hatches, fish spawning, and increased feeding activity. For fly anglers, this means adjusting tactics to match the seasonal food sources that fish are keying in on. While winter fishing is all about small, slow presentations, early spring offers a mix of tiny insects and protein-rich food sources that can entice even the pickiest fish. Knowing what to throw and why can make all the difference between a slow day on the water and a banner one.

Let’s take a deeper dive into the key food sources fish are targeting this time of year and how you can best mimic them with your fly selections.

Midges: The Year-Round Staple

No matter the season, midges are a foundational part of a fish’s diet. These tiny insects make up a large percentage of a trout’s intake, especially in colder months when larger insect hatches are minimal. As spring approaches and the sun rises higher in the sky, midges remain an effective option, but their coloration and behavior begin to shift.

Midge Behavior in Spring

Midges hatch throughout the year, but their colors tend to lighten as the water temperatures increase. In the winter, darker midge patterns—such as black or dark red—tend to be more effective. However, in early spring, green and olive-colored midges become the go-to option. As the water warms, these lighter tones better mimic the midges naturally hatching in the environment.

Another consideration is size. While winter midges are typically extremely small (#22–#26), slightly larger sizes (#18–#22) become more effective as spring progresses. A great strategy is to fish a tandem rig, using a slightly larger midge pattern followed by a smaller one to cover different stages of the midge life cycle.

Recommended Midge Patterns for Spring:

• Zebra Midge (olive, green, or tan) – Size 18–22
• RS2 (gray or olive) – Size 20–22
• Juju Bee Midge – Size 20–24

Mayflies: The First Major Hatch of the Season

While midges remain a staple food source, the first significant mayfly hatch of the year signals a change in fish feeding behavior. Blue-Winged Olives (BWOs) are typically the first mayflies to emerge in early spring, and they bring with them some of the best dry fly action of the year.

BWO Behavior and Timing

Blue-Winged Olives typically hatch on overcast days with light rain or drizzle. They tend to be smaller in size (#16–#22) and can be found in slow-moving water and riffles where fish rise eagerly to take them. Because BWOs hatch in large numbers, fish often become highly selective, keying in on specific life stages of the insect.

For this reason, it’s important to carry a variety of patterns that mimic different stages of the mayfly’s lifecycle. Dry flies such as the Parachute Adams or Sparkle Dun are great for imitating adult BWOs, while RS2s and pheasant tails work well for nymph stages.

Recommended BWO Patterns for Spring:

• RS2 (olive or gray) – Size 18–22
• Parachute Adams – Size 16–20
• Sparkle Dun (olive) – Size 18–22
• Pheasant Tail Nymph – Size 16–20

Eggs: A High-Protein Meal for Opportunistic Fish

One of the biggest events of early spring is the rainbow trout spawn. As water temperatures climb into the mid-40s, rainbows begin their annual migration to shallow gravel beds to lay and fertilize eggs. This process results in an abundance of loose eggs floating in the water, which creates an easy and nutritious meal for fish downstream.

Fishing Egg Patterns Responsibly

While egg patterns are highly effective during the spring, it’s important to be mindful of fish conservation. Spawning rainbows should not be disturbed while they are on their redds (spawning beds). Instead, target areas downstream where other fish—such as brown trout or cutthroats—are actively feeding on dislodged eggs.

Because eggs are packed with nutrients, fish often prefer them over insects during the spawn. Egg patterns in colors such as orange, peach, and pink are particularly effective. These patterns can be fished alone or as part of a two-fly rig with a nymph or midge.

Recommended Egg Patterns for Spring:

• Unreal Egg - Size 12 - 14
• Yarn Egg – Size 12 - 14

Worms: Nature’s Gift from Rising Water Levels

Spring also brings rising water levels as melting snow and seasonal rains swell rivers and creeks. This natural runoff erodes banks, washing worms into the current where they become an irresistible meal for trout and smallmouth bass alike.

Fishing Worm Patterns in High Water

Worms are an excellent food source because they provide more protein than insects, making them a prime target for hungry fish. Because they are naturally found in murky or off-colored water, they work particularly well during high runoff conditions.

When fishing worm patterns, focus on slower seams, eddies, and deep runs where fish hold to escape the heavier current. Pairing a worm pattern with a nymph or egg can create a deadly combination that covers multiple food sources at once.

Recommended Worm Patterns for Spring:

• San Juan Worm (red, pink, or brown) – Size 10–14
• Squirmy Wormy – Size 12–14
• Wire Worm – Size 10–14

Final Thoughts: Adapt to the Season for Success

Spring presents a unique opportunity for fly anglers to capitalize on a mix of insect hatches and larger food sources. By understanding what fish are eating and when, you can improve your success on the water.

Here are a few quick tips for maximizing your early-season fishing experience:

• Match the Hatch: Observe the water for rising fish and insect activity to determine what’s hatching.
• Fish a Two-Fly Rig: Pair a midge or mayfly nymph with an egg or worm to offer multiple options.
• Be Mindful of Spawning Fish: Avoid fishing directly on redds to help sustain healthy fish populations.
• Adjust Depth and Speed: As water levels rise, adjust your weight and depth to get your flies into the feeding zone.

By keeping these strategies in mind, you’ll be well-prepared to make the most of this exciting time of year. Tight lines and happy fishing!