A deviation measure of bilateral symmetry, developmental instability (Fluctuating Asymmetry, FA) was estimated with two different indexes (namely, FA1 and FA11) from the samples of common carp, Cyprinus carpi from different collection sites in a highly polluted Meric river system of Turkey. Researchers used three traits of the carp, i.e., head length, eye diameter and barble length to estimate an index of fluctuating asymmetry separately for each trait (FA1s) and for the all the three traits combined (FA11s). Only FA1 of the eye diameter resulted in significant deviaton from the symmetry when the most polluted site compared to the others. Researchers suggest that developmental instability may be a relevant indicator of pollution as well as the classical markers. We observe as from the study that choice of multiple traits would be helpfull to reveal possible candidates of fluctuating asymmetry for further use in the like model organisms.