Big Sky to Gallatin Gateway, Montana

Best Flies For Gallatin River

Updated Apr 24, 2026, 7:09 AM MDT

Stay subsurface most of the day and cover pocket water fast with a compact stonefly-and-mayfly rig.

Current Conditions
  • Flow: Spring flow is usually clear in the upper canyon but can rise fast with warm weather or dirty tributary input lower down.
  • Water Temperature: Cold water keeps fish grouped in softer current breaks and short feeding lanes.
  • Weather: Clouds help the hatch. Bright sun usually pushes the better fish deeper or tighter to structure.
  • Overall Rating: 6/10
Today's Read

Gallatin River is fishing around blue-winged olives and midges. Start with the patterns below and adjust only after fish show you something different.

Best Flies Right Now
  • Frenchie, size 16-18, nymph
  • Perdigon olive or black, size 16-18, nymph
  • Pat's Rubber Legs, size 8-10, nymph
  • RS2 olive, size 20-22, emerger
  • Parachute Adams, size 16-18, dry
What They Match
  • Blue-winged olives, size 18-20, midday on overcast days
  • Midges, size 18-22, early and late in slower water
  • Small black stoneflies, size 14-16, afternoons near banks and rough edges
How To Fish These Flies
  • Use enough weight to tick bottom quickly in short drifts. The Gallatin rewards efficient high-sticking more than long dead drifts.
  • Target cushion water behind midstream rocks, pocket tails, and the inside shelf below faster riffles.
  • When fish start rising, step into softer current and fish a small BWO or RS2 under a dry instead of forcing a big dry pattern.