Thanks guys, much needed input.
You mention flies from other parts of the world, my thoughts are that anything hungry will try a variety of offerings, learned this from predator hunting , even tho theres no jack rabbits in TN a coyote dont know that, hes hungry and hears something that sounds like a easy meal and decides to go for it.
I always figured fish have some what the same instinct, when they get hungry its time to eat, the fly might look like a bug or fish from another planet but to the fish its an easy meal.
Plus the fact its different may make it more productive, always heard fish get wise to the same ole same ole, but I never asked one to find out.