We determined the efficacy of marking the otoliths of three small-sized progenetic gobies to validate their increments periodicity. These small gobies present high mortalities and rearing difficulties making the direct validation difficult. The otoliths were marked by fish immersion in a bath of alizarin red S (ALR). Fishes were euthanatized and the number of increments in their otoliths laid down after the fluorescent mark were counted and compared with the number of elapsed days. Results validated the daily periodicity of Aphia minuta and Pseudaphya ferreri.  The high mortality hindered the validation of Crystallogobius linearis.