As a general rule, it's pretty much true, but anything can happen especially during the winter. Downsizing can pay off to get big fish especially when they are finicky. During the winter, big fish will not pass up an easy meal even if it's small as long as they don't have to expend much energy to do it. The reverse can happen too, like a dinky 4" perch hitting a 1/4 oz. jighead and a 5" Kalin's grub for example. Go figure.
It also depends on the species. Much of a large trout's diet is made up of tiny insects. However, big trout also like to eat large crayfish or just about anything else that they can catch.
