Parks' Fly Shop: Guide to Other Trout Foods and Flies for the Yellowstone Area, Yellowstone Hatch Chart

Guide to Other Trout Foods and Flies for the Yellowstone Area

Baitfish, crustaceans, terrestrial mammals and uncategorizable food sources such as eggs and San Juan Worms all can be important food items. This page discusses them all and give fly pattern suggestions.

Note that there's a lot of overlap between patterns in this category and others. All streamers are to a degree for example, though most of them are covered here rather than on the Attractors page.

Other Food Items Table

Table Key: X=primary importance, x=secondary importance, blank=unimportant
Name Description Importance Month
      Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Scuds, Sowbugs Most in our area range from tan-gray/olive and #12-16 Primarily lakes, spring creeks, and tailwaters.     X X X x x x X X x  
Streamers: streamlined baitfish Predominant colors should be gray, white, and olive, or combinations. Brighter color combinations also work as attractors. #2-10 Rivers and lakes, primarily for larger fish. Woolly Buggers (considersed attractors and covered on that page) are better choices for medium-small fish. x x X X X x x x X X X x
Streamers: sculpin-like Predominant colors should include olive, tan, and brown, most with pale bellies. Rivers, primarily for larger fish. Use buggers for smaller ones. Especially important in late summer and early fall. x x x X x x x X X X x x
Streamers: large and articulated Predominant colors should include olive, black, and white, plus some attractor colors such as yellow. Big fish flies. Most important in late spring, on summer mornings, and in the fall, especially AM. Don't expect many fish, but big daddies are possible.     x X X x x x X X x  
Crayfish Predominant colors should be red-brown to olive. Only useful on the Lower Madison, Lower Yellowstone, and for carp on the Missouri.       x x x x X X x    
Irritators: small nymph-type Standard nymphs or slightly larger than normal nymphs in bright or noticeable colors designed to attract fish on their spawning runs. Use for pre-spawn fish. Especially important early in the run and over heavily-pressured fish.   x X X       x x X X  
Irritators: large nymph-type Stonefly-type nymphs with hot colors, extra legs, etc. Use for pre-spawn fish. Especially important late in the run or when big pushes of fresh fish are moving (as after rainstorms)   x X x         x X X  
Irritators: small streamer-type Many steelhead flies fit this bill. Most useful for brook trout or just prior to spawning.. Secondary importance to other streamers and nymphs for runners, but useful in lakes for brook trout     x x x X     X x x  
Irritators: large streamer-type Larger steelhead flies fit this bill. Use in place of articulated streamers (much overlap between categories) and for runners.     x x           x x  
Mice Uh, they look like mice. #6 Very extreme changeup from terrestrial imitations. Cutthroats and browns will take them in our area           x x x x      
San Juan Worms Best colors are red, pink, and tricolor. #8-16, large on tailwaters in spring and small otherwise. Most useful on the spring creeks, in tailwaters, and on private lakes. x x X X x x x x x X X x
Eggs Best colors are Creme Delight and Apricot. #12-16 Useful when any larger fish are spawning, especially in spring creeks and tailwaters.   x X X x x     x X X x

Discussion of Insects

Boldface type indicates fly patterns. Italics are used for scientific names.

Scuds and Sowbugs

Around here we basically stick to Minch's Scud and Pink Ostrich Scuds for freshwater shrimp and the Ray Charles for sowbugs. These are most useful in the spring creeks, tailwaters, and on some Park lakes, especially Trout Lake.

Streamers, Streamlined Baitfish

Nowadays this basically means various bunny streamers. We like gray & white, olive & cream, and brown & yellow Double Bunnies, silver and gray or pearl and white Zonkers, and Pine Squirrel Zonkers in olive and brown. Traditional feather-wing and bucktail streamers aren't popular anymore, but still work.

Use streamlined baitfish imitations primarily on large rivers like the Yellowstone and large lakes. Other places, Woolly Buggers typically work best. Woolly Buggers are discussed on the Attractors page.

Streamers, Sculpin-Like

Sculpin-imitating streamers are particularly useful on large rivers like the Yellowstone, though there are sculpins in most of our streams. Don't be afraid to fish them almost dead-drift. We generally fish our own PFS Sculpins in olive, tan, and cree, but the assorted Whitlock-style and other Muddler-type flies also work just fine. Note that we discuss the bright-colored Kiwi and Marabou Muddlers on the Attractors page.

Streamers, Large and Articulated

Very large (larger than #2) and articulated streamers are generally only useful when covering lots of water on big rivers like the Yellowstone or Madison, since they'll spook most trout smaller than 16-18 inches. These are the ideal big fish hunting flies for most PFS guides, but be sure to fish a smaller nymph or small streamer off the back in order to keep your numbers up, because you won't get many chances on such large flies (most we use measure 4-6" in length). The fly in this category we use the most are Double Buggers, but other Galloup-style articulated patterns like Love Bunnies, Sex Dungeons, Silvey Sculpins, and our new Scleech also work great. Lots of overlap between these and Attractors.


Crayfish are very important flies on the low-elevation Lower Madison, less important on the Lower Yellowstone, and generally not important on other local trout rivers. They are critical for Missouri River carp, however. For trout we like Clouser Crayfish, while carp prefer a fox squirrel over gray squirrel Clouser Minnow.

Nymph-Type Irritators

We consider Irritators/Aggravators to be flies that have the shape of other nymphs, whether imitative or attractor, but colors or other elements that cannot possibly seem natural to the trout. Purple, chartreuse, red, and orange are good colors to try when trying to entice pre-spawn trout with small irritators, while large irritators should resemble normal stonefly nymphs but include extra legs and "hot spots." Minch's Creep is a good example. It's a sparkly black Girdle Bug with eight legs and a hot orange flash chenille head. Lots of overlap between these and Attractors, especially between flashier attractors and drabber irritators.

Streamer-Type Irritators

In small sizes (#8-12), these (basically bright-colored) streamers are great for brook trout. Somewhat larger sizes (#2-6) are good all around flies for lake trout and also work well for aggressive cutts, rainbows, and browns. Anything bigger is only useful for large and/or run-up fish. Lots of discussion of some of these on the Attractors page.


Once in awhile you can get a big cutt, rainbow, or brown on a mouse, especially from Slough Creek or near big log jams. Also good for 2AM fishing on the spring creeks. Not very useful otherwise.

San Juan Worms

San Juans are most useful on spring creeks and tailwaters, but see some utility on freestone rivers after rainstorms and at the immediate head of runoff. We like red and pink, plus the White River or Tricolor Worm by Walter's cousin. Check it out on our Youtube Channel.

Egg Flies

Egg flies are underutilized around here. People might fish them in spring and fall when rainbows and browns are spawning, respectively, but whitefish and suckers use sizable streams to spawn in early fall and early summer, respectively, making eggs available for much of the season. These are a super food for fish as well as people, packed with protein and fat. Keep them small. Most commercial versions are far too large. We mostly use #14s. Apricot and Creme Delite are our favorite base colors, and more often than not those we tie get a red eye spot.

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