Obviously, there are many other food sources for trout besides the aquatic insects and terrestrials. Trout feed on scuds (small crustaceans), aquatic worms, leeches, bait fish and more. The flies that imitate them are numerous in numbers and size. These flies can be dead drifted, swung and stripped – slow or fast. The best technique is to attempt to fish these flies how they act while they are in the water.