Recently, the severe damage of coral reef areas in Andaman Sea and Gulf of Thailand has been suffered by coral bleaching. This phenomenon was resulted from the released of symbiotic Symbiodinium sp. (zooxanthellae) from the coral host and other invertebrates when the average temperature of seawater increased to about 1-2°C higher than the average normal temperature. Once bleaching begins, the symbiotic zooxanthellae will be expelled from the host and tends to continue even without continuing stress, which leads to a lighter or completely white appearance and then the coral has no longer to survive. If the coral colony survives during the stress period, zooxanthellae in coral tissue often require weeks to months to return to normal density. To restore/conserve the coral reef areas many research projects have concerned on the coral propagation via sexual process and asexual process by snipping fragments of donor colonies, mounting it on small disks, and submerging it under water to start new colonies. The research on zooxanthellae culture has been carried out as for the rehabilitation of zooxanthellae cells into those breached coral and also into coral eggs and larvae of coral during the sexual process which is the trigger for growth and survival of the newborn coral. In this study, zooxanthellae from coral and sea anemone were isolated and maintained in 4 different of culture medium. The best culture medium for growth of zooxanthellae will be selected to conduct the experiment with five levels of pH. The results revealed that Daigo medium at pH 6.5, 7 and pH 8 were optimal to maintain those zooxanthellae cells from coral but no cell division was observed while zooxanthellae from sea anemone have high growth rate in all culture medium.