The three-spined stickleback (Gasterosteus aculeatus) and the parasitic tapeworm Schistocephalus solidus are well-studied subjects for studies of host-parasite interactions. Previous studies show that S. solidus infection cause three-spined sticklebacks to seek out shallow water and water close to the surface. This kind of host manipulation is thought to increase S. solidus chances of transmission to their definitive host, a piscivorous bird. The mechanism behind this manipulation is unknown, that is, how S. solidus entices the three-spined sticklebacks to seek out shallow, inshore waters. The aim of this study was to find out if this is achieved by altering the light and temperature preferences of the three-spined stickleback through laboratory experiments. An arena with a light gradient was used for the light preference experiments. An arena where the sticklebacks could choose between colder and warmer temperatures was used for the temperature preference experiment. My results indicate that infected three-spined sticklebacks preferred darker areas and moved less than uninfected individuals. No difference in temperature preference was observed but the results of the experiment should be interpreted carefully since few individuals were infected. Experiments under more natural conditions and field studies are suggested to gain more knowledge on S. solidus host manipulations.