We investigated the hypothesis that strontium:calcium (Sr:Ca), cadmium:calcium (Cd:Ca), and barium:calcium (Ba:Ca) composition in scales reflects that of the ambient seawater in which fish were reared under controlled experimental conditions. Juvenile spot (Leiostomus xanthurus) were held in replicate tanks containing four different concentrations of Sr, Cd, and Ba maintained at either 20 or 25°C for a total of 42 days. The elemental composition of scales from these fish was analyzed at the termination of the experiment, using isotope dilution inductively coupled plasma mass spectrometry (ICP-MS). Sr, Cd, and Ba levels in the scales, expressed as ratios to Ca, were linearly related to environmental concentrations, indicating that the elements were incorporated in constant proportions to levels in the ambient water. Temperature had no measurable effect on the uptake of Sr, Cd, or Ba into the scales. Finally, Sr:Ca and Ba:Ca ratios in scales were highly correlated with levels in the otoliths from the same treatment. In all, Sr:Ca, Cd:Ca, and Ba:Ca signatures in scales appear to be representative of the ambient environment and, therefore, may be useful for quantifying life-history characteristics of individual fish.