The research methodisexperimental method. Materials usedin this study wereselectedbacterial isolatesof BacillussubtilisstrainVITNJ1isolated fromthe digestive tractNila Tilapia(Oreochromis niloticus). The purpose ofthis study was power test antagonistic activity against pathogenic bacteria, test resistance toacids and bases, studiedthe form of bacterial growth curve and test candidate probiotic bacterial attachment. Of an timicrobial test against Aeromonas hydrophilais known that the bacterium Bacillussubtilis has the ability toinhibit bacterial growthinhibition zonetestwith a diameter of13mm. cangrowon a variety of pH ranges(2, 3, 4, 5, 6, 7, 8, 9, 10and11), sigmoid shaped growth curve, can beattached to thestainless steelto109dilution.