Previous field studies suggest that the preference for an optimal temperature is often overridden by a stronger preference for other habitat variables such as physical structure. I used a temperature gradient tank with various treatments of ration, prey availability, and cover to test the relative importance of these factors in conjunction with temperature on habitat selection by individual smallmouth bass Micropterus dolomieu. The presence of food and cover (presented in separate experiments) significantly affected the temperature selected by smallmouth bass. Fish presented with a limited amount of food at a position of greater than preferred temperature in the tank increased the time spent at high temperatures, whereas fish allowed to feed till satiated retreated to the cold end of the tank for most of the day. When cover was present at the warm end of the tank, the mean time spent in this area was five times greater than when no cover was present in the tank. The preference for cover at high t...