Laboratory experiments have demonstrated that the change in the height of dispersal of Calopteryx splendens Harris larvae on perches is a protective strategy in the presence of fish. Specificity of protective behavior of damselflies in the presence of pelagic or bottom-dwelling fishes, or of a complex of both types of fishes is described. The effectiveness of the habitat choice is reduced in the presence of the complex of fishes. The use of an optimal protective strategy by all the larvae was observed only in the case when their population density was the lowest. The increase in the population density resulted in the increased importance of intraspecies competition (cannibalism) and decreased effectiveness of protective behavior against heterospecific predators.