How to Pick the Right Fly (Part 6): Scuds, Sowbugs, and Terrestrials 101

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2wt fly rod

This is the sixth article in our series on how to pick the right fly for any fishing situation. To see all the posts in this series, click here.

By Spencer Durrant

Imagine you’re on the high school basketball team. You get to travel to all the road games, you bask in the general adoration the school showers on you, and you enjoy the time away from class. But there’s just one problem – you ride the bench. You’re not a starter. You only get garbage time minutes, when the coach decides you can’t do anything to mess up the game’s outcome.

If scuds and sowbugs had feelings, they might feel that way. They’re aquatic insects, but they don’t get the same love mayflies and caddisflies do. We all probably have a scud and sowbug pattern in our boxes, but we don’t call on them nearly often enough.

Terrestrials, on the other hand – they’re like football players. Great at what they do, but they’re only effective a few short weeks out of the year.

All kidding aside, I do think we tend to overlook the value of scuds, sowbugs, and terrestrials as anglers. Today, we’ll take a look at different situations when you want to use these bugs, as well as some go-to patterns that you can fish with confidence.

Scuds and sowbugs – what are they?

While you may hear these bugs referred to interchangeably, they’re not. A scud is a different insect from a sowbug, although they’re incredibly similar. The folks over at The Missoulian Angler put it best: “A scud is oval in shape while the sowbug has a flat profile. Both behave the same in the water, as both are basically freshwater shrimp.”

That’s the best way to think of these aquatic insects – they’re freshwater crustaceans. According to guide – and noted bug expert – Pat Dorsey, scuds are commonly found in tailwaters and spring creeks. That’s because they prefer rivers with relatively stable flows and temperatures, which you’ll find in both those water types.

How to fish them

There’s no trick to fishing a scud or sowbug pattern. These are nymphs, so you’ll fish them as part of a nymph rig. Both of these bugs work best when fished as a bottom fly, or very close to the river bottom. Scuds and sowbugs generally don’t move far up the water column.

When to use them

If you’re ever on a tailwater or spring creek, you’ll want some scuds and sowbugs in your box. Scuds are also must-have patterns for fishing lakes. Some of the best brook trout I’ve ever caught came on a scud.

There is no “hatch” of scuds or sowbugs, since these aquatic insects don’t ever leave the water. They’re a fairly abundant food source in tailwaters and spring creeks, so you can fish them year-round and see some success.

Must-have patterns

Most of these patterns are just rehashing the same basic shape, but there are a few that are absolute must-haves. Get them in sizes 14 – 18.

  • Standard Scud – get this pattern in pink, grey, and brown. These are some of the most common colors because they’re just flat-out effective.
  • Ninch’s Cotton Candy – this was developed on the Missouri River, but patterns in this style work well just about anywhere.
  • Ray Charles – the OG scud pattern.

You can always look through our Baker’s Dozen pack of nymphs that include scuds and sowbugs, as well.

Now that we’ve wrapped up these small nymphs, let’s move on to some bigger, meatier dry flies.

Terrestrials – what are they?

Terrestrials – they’re wonderfully fun to fish, but they’re not available year-round. They’re like our annual fall pumpkin spice craze. When they show up, they’re everywhere, and that’s all anyone wants. Once December rolls around, though, we’ve dumped pumpkin spice for peppermint.

That’s how it is with terrestrials. The window to fish these bugs is shorter than most other insects, but it provides some of the best fishing you’ll have all year.

In short, terrestrials are insects that live on land, but sometimes end up in the water, where trout readily eat them. Grasshoppers, cicadas, and ants are the most well-known terrestrials.

How to fish them

Fishing terrestrials is just like fishing any other dry fly. You need a good drift in front of places where trout are likely to hold. In the case of grasshoppers, ants, beetles, or other insects, trout are most likely to take them closer to the bank. These bugs tend to fall off, or get tossed around by the wind, from their perch on trees and grass near the water’s edge. When they fall in the water, they make more of a splash than a dainty mayfly does when it lands on the water. So, the big difference in fishing terrestrials and other dry flies is that you’ll usually want to slap the water a bit with these patterns to make them look realistic.

Try doing something like this:

That’s easier said than done, but it’s a wildly effective tactic.

When to use them

Terrestrials don’t “hatch” in the way aquatic insects do. Cicadas will emerge from their subterranean hidey-holes, but grasshoppers and ants end up in the river largely by chance or get blown in by a gust of wind.

With that said, we do have some “hatch charts” that depict when the best time is to fish certain terrestrial insects.


Fish these from late June through the first big freeze in your area – anywhere from late September to November.


Cicadas have a short window that varies from river to river. In general, though, June through August is the prime time for cicadas.


Their season is similar to hoppers. Late June through the first big freeze.

Must-have patterns

If I could only pick one terrestrial pattern to fish the rest of my life, it’d be a Chubby Chernobyl. It’s a do-all foam fly that imitates hoppers exceptionally well, but it can work as a cicada, ant, or stonefly if you’re in a bind.

Aside from the Chubby Chernobyl, there are a few other terrestrial patterns that you should have in your fly box:

  • Dave’s Hopper – this is a classic hopper pattern that’s been great ever since it was invented. Sizes 10-12 are great for this fly.
  • Foam Cicada – this is the basic pattern for imitating cicadas. You’ll want it in sizes 10 – 12.
  • Black Ant – another classic that’s proven its worth over decades. Sizes 12-16 are perfect for this fly.

Hit the water

With a box full of scuds, sowbugs, and terrestrials, you’re ready to hit the water just about any time of year. Scuds and sowbugs, in particular, work well year-round. They’re not quite as dependable as midges, but you better believe I have a few dozen scuds in my box at any given moment. They’re a versatile bug that works in both rivers and lakes.

I always have some hoppers in the box, too. They work great as the top fly in a dry-dropper rig, even in the winter. I prefer to use a dry fly as my indicator when nymphing because it’s more sensitive than most indicators.

Regardless of how you use them, these flies are a valuable addition to any fly box. Grab a few, tie some up, and get those boxes stocked up!

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