If you don't know about the cloud trail, it's time to learn what fly fishing for carp is all about.
Fly fishing for carp is not easy. As a matter of opinion, carp on the fly are one of the most challenging fish to chase. Carp are spooky, sensitive, strong fighters, and can be fairly picky regarding which fly they're going to eat. One day, a carp will crush one pattern, then the next day have nothing to do with it. However, when chasing carp, finding a carp cloud trail will increase your odds of a hookup significantly.
Very recently, I went carp fishing with my trusty 5-6wt Walton. I like to get out on the water very early to watch for tailing carp. Just like bonefish, presenting to a target is a rush, but you only get one or two shots before it's all over. In this case, I didn't see any tailers, so I went and stood on top of a nearby bridge and just watched the water. As luck would have it, a little deeper off the bank, I saw a cloud trail. I couldn't see the carp, but I sure saw the path it was taking as it sucked and ate along the bottom.
As quickly as I could, I ran as fast as possible in my waders down the side of the bridge and into the river near the general location where I marked the cloud trail using a tree as a waypoint. Once down there, I was able to hone in on it, present my fly a few feet in front of the direction the cloud was going, and the fight was on. I couldn't believe it worked. It was awesome.
After that fish, I did it again. Back on the top of the bridge, I went and stood around for about 20 minutes. Then all of a sudden there was a cloud trail on the other side. From there, it was the same technique that worked like a charm.
The Cloud Trail
An actively feeding carp in deeper water makes a cloud trail as they turn over rocks and break up weeds looking for food. They oftentimes don't really discriminate when they are being this hungry. Just about any well placed fly will get the job done if you can accurately get it in the right pie plate sized bullseye in front of the fish. However, this is where things get tricky. If you hit the water too hard with the fly, the carp is gone. Strip too fast, you can spook the fish. If you set too soon, you'll never feel it. If your drift isn't right, your fly won't look natural. These things are all just some of the fun that goes into fly fishing for carp.
Now, speaking of the above bridge technique, I'm not sure if there is a name for that or not. If not, I'm going to copyright it when I think of something snappy.