Occurrence of copper acclimation in the least killifish Heterandria formosa, and associated biochemical and physiological mechanisms

► The occurrence and the underlying mechanisms of Cu acclimation were investigated in the least killifish. ► Mortality is an effective endpoint of showing Cu acclimation, but also reduced Na loss and lipid peroxidation. ► Acclimation appears to be due to an increased induction of metallothioneins. ► Also a reduction in the rate of Cu accumulation, sodium loss and a reduced loss of catalase activity could play some roles.