The variability of morphological characters was studied in a population of spined loach from Klawój Lake karyologically identified as a pure diploid C. taenia (2n = 48). 24 metric features were used to calculate correlation coefficients and linear regressions to determine the relationships between metric features with total length. As regards 11 meristic features, females had more lateral and predorsal spots than males. Statistically significant differences between males and females were also found in mean values of 15 metric indices. Age variability in the shape of the lamina circularis of males was revealed.