This chapter reviews parasite avoidance behaviors in fish. One underlying theme of the chapter is that the large number of studies on mechanisms of detection and avoidance of aquatic predators provides a solid theoretical and empirical foundation for future studies involving parasite avoidance. The chapter focuses on avoidance behaviors of parasites that actively infect their host, primarily because the stages tend to be relatively large and perhaps more easily detectable. It describes the shortage of supportive evidence for parasite avoidance behaviors in fish. Avoidance of conspecifics has also been evaluated in the context of shoaling behavior. Fish hosts have some options for behavioral management of parasite intensities after parasites have successfully contacted the host. Evaluation of behavioral fever in fish exposed to other types of parasites would be a useful addition. Predator-induced reductions in fish activity have strong negative effects on the foraging behavior of individuals.