Saying how fish travel i can personally say(without crossing any fingers) that i have seen carp up to 15 inches long traveling upstream from my lake in a canal 20 inches wide and 8 to 10 inches deep. I dont know where they go but they must be going somewhere great to leave where they are coming from. Also i have a pond that when we had 9inches of rain one night 2 years ago got bass, carp, shad, shinners, bluegill, and crawfish from the tank running around.