Someone mentioned carp in large lakes. I have a place on fairly large
lake - maybe 18 miles long. It has a substantial population of carp but
they are hard to catch on a fly. When you catch one, they do their best
to empty your reel. They never jump, but a 15 pounder can rip a lot of line.

Anyway, we started feeding them dry dog food so the kids could watch
them. One day I took some gray wool and made a "dog food fly". They went
right for it. I don't fish for them often because I don't want to scare
them away, but once in a while it's fun to catch a fish that size.

At the lake I have never been able to make a link between normal daily
weather changes and seeing them.