Phenotypic plasticity is defined as an organism’s ability to express differentphenotypes depending on the environment. Predation is one of the key forces inecology and can indirectly cause a change of the phenotype in fish populations.Pigmentation change in order to match the background is one type of camouflage usedin fish and other organisms. Moreover, pigmentation might depend on environmentalconditions such as turbidity and water colour that affect the light spectrum and thusthe visibility in the water. The phenotypic variation in body pigmentation of perch(Perca fluviatilis L.) has rarely been studied to this date. In this study, I examined ifbody pigmentation of perch varied between different environments and betweenstructurally different habitats (littoral/pelagic). I tested long-term (phenotypicplasticity) and short-term (physiological-behavioural) changes in pigmentation byusing long-term pre-treatments and short-term aquarium experiments. Differences instructurally-diverse habitats were investigated in an extensive field study.Furthermore, experimental results were compared to data from the field. The resultsshow that pigmentation is determined by environmental factors, such as water colouror turbidity, and by structural complexity. Since fishes adapted their pigmentation totheir visual environment, pigmentation is likely used as predator avoidancemechanism in perch. Moreover, it was demonstrated that the environmentally-inducedpigmentation pattern determines the magnitude of short-term pigmentation in perch.