Trout feed first by sight, which includes size and shape, color and movement. Once the fly is in the mouth of the fish it then tastes the fly by crushing it in its mouth. If the texture and taste is not correct the food item will be expressed. In fishing a natural worm you will often feel a tap, tap, tap as the fish crushes the worm, tastes the worm and then it will swallow it. In fly fishing with artificial nymphs, including worms, there is rarely a second tap as the texture and taste of most flies is not here. Not so with the Worm. The reason the Worm fished so well is that it looks more realistic than other patterns, it has more natural movement and it has the texture of flesh that is similar to a real worm. Fish hold it longer in their mouth which gives the angler a little more time to detect the strike. Fish the Worm.