Choosing kebari when fishing over rising trout, the logical conclusion one might reach would be to imitate the fish's diet as precisely as possible in order that our artificial might be accepted as food. However, there are many reasons one could make a case against this approach. I have successfully used completely different appearing flies under similar circumstances with a reasonable degree of success. Certainly much more successfully than the "Match the Hatch" approach.
First, we have to understand that a fish is an opportunist as are most life forms on this planet. For example, observation of a trout in it's natural environment will show that anything which even remotely appears to be something to eat, and even things that do not will be sampled. The shear amount of debris in a stream far outnumber the actual edible food items, so for a trout it's a numbers game. The percentage of edibles just has to be sufficient to provide the energy to search for them. Of course, the success rate needs to be somewhat greater if a fish is to grow larger, not simply to survive. Some streams provide that, some do not.
In slower water a fish can take time to try out a great variety of potential fare. Many times I have observed a trout try the same object two or three times before letting it settle to the bottom. That's assuming that a different trout will not pick it up and try it for himself, which they almost assuredly will.
Now in faster water, a fish only has a second or two to decide whether or not to take the "energy-robbing" plunge into the current to try out an interesting looking tidbit. These trout behave differently and are more selective of what they choose simply because they have to be. Their survival depends upon it.
Let's look at the classic "Match the Hatch" situation. You are "in-stream" and aquatic insects are hatching all around you. The fish seem oblivious to distraction, so focused are they on feeding. Put yourself in the trout's place. You don't have to go searching for nourishment, or try out every possible stick or leaf bit. The food almost flows right into their mouths.
Now down the current comes your imitative fly. Will the trout notice it? I hate to tell you but the odds are against it. That is the kind of boxed-in thinking that we need to reconsider. Out of thousands of hatching insects, your nearly exact match may or may not be noticed. And often it is not. What we need to offer the fish is something that will make them notice and react. Depending upon conditions and depth of presentation, this might be a hopper, streamer, crayfish or a hellgramite. All are good bets. The approach might be to make the fish angry, or just offer a bigger mouthful. These patterns don't need to look exactly like their natural counterparts, they only need to attract attention.
So the strategy in such a situation, is to offer something much larger and/or flashy, colorful or with a unique action or sound. The goal at this point is just to present something bigger or potentially outlandish at the correct depth for it to be noticed. It helps even further if you use a fly that you are familiar with, one with which you have become skilled. This approach may just be the ticket to upping the angling odds for you.
Most patterns based upon Eastern Tenkara tactics are rooted in this concept, but Western patterns can be just as useful. It's the action, the bright color, the flash or sound which advertises it's presence, proves the ability to attract attention, and finally allows you to connect. Does "Match the Hatch " strategy work? It surely does or it would not have stood the test of time. But it's not the only game in town, and may not be the best bet for your next trip.
Photo Courtesy: National Park Service