I dont think so....not always. I fish a pool with trout that AVERAGE 18 inches (stocked private water that I occasionally get permission to fish) where the fall fish and trout co-exist. I'm sure there are some good meals to be had by the trout, but they hardly clean them out judging by the many fall fish I catch there. By the way, my streamers that most resemble small chubs dont catch fish there!
Jim
Jim