There are various problems related with probiotic products containing Bacillus species available in Thailand and other countries such as high cost and ineffectiveness ( Nimrat and Vuthiphandchai, 2011). Recently, Nimrat et al. (2011) developed an effectively novel probiotic for rearing of L. vannamei through microencapsulated or freeze-dried forms of microbial probiotics: bacteria, yeast and microalgae. Species composition of bacterial probiotics remains to be investigated on their effect of growth, survival and microbiological aspects in order to increase efficacy and reduce complication of production processes. The purpose of this study was to investigate the efficacy of species composition of Bacillus as microencapsulated and freeze-dried forms on growth, bacterial numbers and water quality during rearing of L. vannamei larvae and postlarvae.