A non-lethal method providing growth tags is a precondition for many in-vivo experiments investigating growth of marine invertebrates. This study determines the effectiveness of Calcein, Alizarin Red and Strontium chloride hexahydrate in marking Argentinean surf clams (Donax hanleyanus) under controlled conditions. Wild specimens, collected from Faro Querandi (Buenos Aires province, Argentina), were taged using different concentrations of each stain and several immersion periods. After marking, animals were reared in an aquaculture system to allow growth. Mortality, body condition and growth rate were measured for 20 days to assess the effects of the treatments. To detect the incorporated marks, shells were cut and sections analyzed using scanning electron microscopy for Strontium chloride hexahydrate and fluorescence microscopy for Calcein and Alizarin Red. Results demonstrate that Calcein was the best growth marker as it provides a long-lasting, readily detected fluorescent mark that can be used to measure shell growth accurately, even at low concentrations and immersion periods. In addition, marking with Calcein did not affect survivorship or growth and thus is considered to be the best stain evaluated for Donax hanleyanus.