What hatches in July: flies and patterns

12 entries in the Hatch Window curated chart are typically active in July, with the fly patterns that match each.

By water type

• Tailwater: Midges, Caddisflies (general), Pale Morning Dun, Trico, Hoppers, ants & beetles, Scuds & Sowbugs, Yellow Sally (Little Yellow Stonefly)
• Freestone: Midges, Caddisflies (general), Salmonfly / Golden Stonefly, Pale Morning Dun, Green Drake (Western), Hoppers, ants & beetles, Isonychia / Slate Drake, Hex (Giant Michigan Mayfly), Yellow Sally (Little Yellow Stonefly), Light Cahill
• Spring creek: Midges, Caddisflies (general), Trico, Hoppers, ants & beetles, Hex (Giant Michigan Mayfly), Scuds & Sowbugs, Light Cahill

Hatches and matching patterns

Midges

• Zebra Midge (nymph, size 18-22)
• Griffith's Gnat (dry, size 18-22)
• Rojo Midge (nymph, size 20-24)

Year-round on tailwaters, most reliable hatch on cold winter days when little else is moving.

Caddisflies (general)

• Elk Hair Caddis (dry, size 14-18)
• Sparkle Pupa (emerger, size 14-18)
• LaFontaine's Deep Sparkle Pupa (nymph, size 14-16)

The spring "Mother's Day caddis" emergence is a marquee Western event on rivers like the Arkansas.

Salmonfly / Golden Stonefly

• Chubby Chernobyl (dry, size 4-8)
• Stimulator (dry, size 6-10)
• Pat's Rubber Legs (nymph, size 4-8)

Large, loud, and short-lived; hatch progresses upstream with warming water, so timing follows elevation.

Pale Morning Dun

• PMD Sparkle Dun (emerger, size 16-18)
• PMD Parachute (dry, size 16-18)
• PMD Pheasant Tail (nymph, size 16-18)

Classic summer morning hatch on tailwaters; fish are often selective to exact size/color.

Green Drake (Western)

• Green Drake Parachute (dry, size 10-12)
• Green Drake Nymph (nymph, size 10-12)

A big-bug event on the right high-elevation freestones; can bring up the largest fish in the river.

Trico

• Trico Spinner (dry, size 20-24)
• CDC Trico Dun (dry, size 20-24)

Early-morning spinner falls; tiny flies and light tippet, technically demanding but very reliable on Western tailwaters and Eastern/Midwest spring creeks alike.

Hoppers, ants & beetles

• Dave's Hopper (terrestrial, size 6-10)
• Chernobyl Ant (terrestrial, size 8-12)
• Foam Beetle (terrestrial, size 12-16)

Late-summer bank-water staple, especially on windy afternoons.

Isonychia / Slate Drake

• Isonychia Nymph (nymph, size 10-12)
• Slate Drake Dry (dry, size 12-14)
• Adams (dry, size 12-14)

A strong-swimming nymph often fished in the margins during high water; the dun hatch runs through late summer into early fall.

Hex (Giant Michigan Mayfly)

• Michigan Wiggler (nymph, size 4-8)
• Hex Dun (dry, size 4-8)
• Hex Spinner (dry, size 4-8)

An after-dark event on Midwest rivers and lakes with silty/sandy bottoms; short and intense, it can bring up the biggest fish of the year.

Scuds & Sowbugs

• Scud (olive/tan) (nymph, size 14-18)
• Sowbug (nymph, size 14-18)

Not a hatch, a year-round staple on cold, stable tailwaters and spring creeks (the South Holston and Clinch in Tennessee, the Bighorn and San Juan out West, Pennsylvania limestoners, the Driftless Area) where crustaceans outnumber insects.

Yellow Sally (Little Yellow Stonefly)

• Yellow Sally Dry (dry, size 14-16)
• Yellow Stimulator (dry, size 14-16)
• Little Yellow Stone Nymph (nymph, size 14-16)

A small, bright-yellow summer stonefly found across Western, Northeastern and Southern Appalachian streams; fluttering egg-layers draw fish on warm afternoons and evenings.

Light Cahill

• Light Cahill Dry (dry, size 12-16)
• Light Cahill Comparadun (dry, size 14-16)
• Light Cahill Nymph (nymph, size 12-16)

A creamy, pale-yellow evening mayfly of late spring and early summer across Eastern, Midwest and Southern Appalachian freestones; a classic dusk dry-fly hatch.

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