With its cool beginnings in Grebe Lake the Gibbon shows as much variation as any river in Yellowstone Park. Until it reaches Elk Park the Gibbon isn't particularly worth fly fishing. By the time it gets there it has gained enough nutrients and volume to be a good trout stream. It meanders through the meadows as beautifully as any trout stream and is a sheer pleasure to fish.
From the meadows down the Gibbon is more of a rough and tumble trout stream until it reaches National Park Meadow, where it joins the Firehole to form the Madison.
This river is best fished as two different streams, a freestone stream and a meadow stream. Fish the rough and tumble water with a high riding dry fly, hitting the good spots and covering lots of water. The meadow water needs to be fished more carefully. Some useful patterns are Blue Winged Olive, Pale Morning Dun, Elk Hair Caddis, Peacock Caddis and lots of hoppers for mid July on.
If there is no surface activity try a Copper John, Pheasant Tail Nymph or small Woolly Bugger when the water is somewhat silty.