Photo by Les Korcala

Mahogany Overview

  • Family: Mayfly
  • Size: 11-13mm (Size 14-16)
  • Emergence: Mid September through October
  • Emergence Time: Afternoon

Fly Fishing The Mahogany

The Mahogany hatch is the last sizable mayfly hatch of the year in Montana. Coming in at a size 14, you can see them, and so can the fish.

The Mahogany hatch rarely reaches blanket state, so when they’re on, the fish are not always as picky about stages. A cripple, parachute or any adult pattern will usually work.

Another thing to consider is air and water temperature during the hatch. The colder it is, the longer it takes for the hatch to establish. More importantly, it doesn’t take a lot to spook fish, and they don’t come back, because the cold is slowing the fish down. Careful wading is essential and when fishing a pod in a Mahogany hatch, try and take the biggest trout first. Because catching the smaller fish at the back of the pod will spook the larger fish. In summer, the fish return to feeding quite rapidly. Not so for the Mahoganies. Pick your targets well, because the fish won’t stay there forever if you’re catching them.

Missoula Mahogany Fly Fishing

You’ll find pods on the Clark Fork River and Bitterroot River, and in the right spots, rising fish on Rock Creek. The Blackfoot River has Mahoganies, but later in the season sometimes the river is too cold for the fish to come up and rise.

Mahogany Nymph

Don’t lose sight of the Mahogany nymph. Even if the fish aren’t moving to the surface, the nymphs are moving, and the trout recognize them. A larger Pheasant Tail or Brown Perdigon will take fish all day in fall. The colder the day, the deeper your nymph needs to be, and on the colder days, don’t be afraid of the sun.

Sunny Mornings

The sun will help warm up the water and get the fish moving. If it gets cloudy in the afternoon, so much the better, but the sun will move the fish to the hatching Mahoganies and October Caddis.

Additional Mahogany Resources