I have spent many days in the fall around southwest Montana rowing clients around and tying on flies over the years. I can say that honestly, the October Caddis hatch is a bit disappointing. Have we caught trout on dries? Yes, more on the nymphs, but it’s just one of those hatches that should be better that it is in our area.
I don’t believe that I have ever seen more than about five adults in any one outing in a section of water. When you do see one, you know exactly what it is. This last caddis of the season is more moth like. It is a huge, lumbering caddis. The adults are sized 10-12, making it a great pattern to prospect our area rivers with a nymph below. I believe that there are generally more October Caddis around then I tend to notice, but unlike their smaller cousins, you don’t see them in bigger numbers on a given day. I have had clients catch some great trout on both the nymphs and dries, but it is very hit or miss, in my experience.
When fall water temperatures cool off, we generally start nymphing in the morning. If the trout try to eat the indicator here and there, it’s time to put on an October Caddis. Many of our area rivers such as the Lower Madison or Missouri River can get overwhelmed with weeds growing from the stream bed starting in August and tending to die off in late September. A great way to fish when there are many weeds are present is to throw a large dry with a nymph dropped below it, keeping your flies out of the “salad”.
Another technique is to skittering them on the surface of the water. This can draw some explosive strikes. Just like twitching a hopper, you want to give them action on the water, but not move it too fast, where a hungry trout may miss it. Give it a twitch, let it sit for a few seconds, then another twitch.
Even though this may not be a hatch to make you book your Montana fly fishing immediately. If you happen to be in Montana on a beautiful fall day, keep your eyes open for a possibility to throw a big dry fly at an eager trout.