Abstract: In the present study, we examined the potential uses of Alizarin complexone and Alizarin red S to mark S. grahami larvae and juveniles. Individuals of different ages (6 days, 20 days, 90 days) were immersed in four concentrations of a solution of each chemical (50, 100, 150 and 200 mg/L) for different periods of time (4-36 h). Marked individuals were euthanized 4-27 days after immersion, and the lapillus was removed and used to determine mark quality. After marking with 50-150 mg/L ALC and ARS, violet marks were visible under normal light, and scarlet fluorescent marks were visible under 510-560 nm green light. The clear marks under normal light were recorded, and a 100% survival rate was guaranteed under the following conditions: 6 day old larvae immersed in 50 mg/L ALC or ARS for 8h; 20 day old larvae immersed in 50 mg/L ALC or 100 mg/L ARS for 24h; 90 day old juveniles immersed in 100mg/L ALC or 150 mg/L ARS for 24 h.