The Rainbow Trout is a cold water species that needs clear water and temperatures below 70 degrees. In small ponds they are sometimes used to control Bluegill populations. Adult Trout are stocked in the late fall. After the trout feed on Bluegill through the winter months, they can be harvested in the spring. Any remaining trout will die off when water temperatures exceed 75 degrees. This practice eliminates any permanent population of a second predator in your pond. (this assumes existing Largemouth Bass populations).