Herbicides are chemical substances with selective toxic action (limited for some vegetal species) or general (for any species), used to fight against weeds in the crops, fruit and grapes-growing fields, parks etc. The administration of herbicides though has complex effects on the biocenosis. In the aquatic environment, they have proved to be toxic not only for the aimed plants, but also for numerous species of animals. The deterioration of the aquatic environment is accentuated by the fact that plants that had died due to the treatment decompose themselves in a rapid manner, leading to the decrease of the oxygen level in the water, the final consequence being the increase in the death rate of the animals. This paper has studied the action of the Dual Gold 960 EC herbicide in different concentrations on some physiological indicators for the Prussian carp (Carassiusauratusgibelio Bloch 1782). The herbicide has had an inhibitive effect on the researched parameters for all the used concentrations.