Abstract: We used alizarin red S (ARS) and calcein (CAL) to dip black porgy (Acanthopagrus schlegelii) of two sizes by fluorescent markers technique. Acute staining results show that ARS and CAL had no significant effects on the survival rate of the juveniles of both sizes. Subsequent breeding test shows no significant effects on juveniles of both sizes. The markers effects of ARS and CAL on hard tissues of the juveniles increased with increasing dye concentration, but the markers effects of ARS were better than those of CAL. No significant difference was observed for ARS, but the marker effect of CAL of small size was better than that of big size. The marker effect of ARS of fin spines was the best, followed by scales and fins, and the worst was that of otolith. CAL marker effects were at the same level for spines, fins and scales, followed by otolith. ARS marking technology has more application and research value.