<![CDATA[Poor water quality is one of the main obstacles in the cultivation of vannamei shrimp (Penaeus vannamei), because it can cause stress, decrease immunity, increase susceptibility to diseases, and inhibit growth. Fluctuations in water quality parameters such as temperature, pH, salinity, and dissolved oxygen (DO) greatly affect the physiological processes and metabolism of shrimp. Bacillus spp. It is expected to be able to improve water quality through the process of decomposition of organic matter, reduction of harmful compounds, and maintaining the microbiological balance of aquatic ecosystems. This study aims to examine the effect of giving Bacillus spp. on water quality and growth rate of vannamei shrimp. The research was conducted experimentally with a quantitative approach using a one-factor Complete Random Design (RAL), consisting of five levels of treatment with three replicas, so that 15 experimental units were obtained. The treatment consisted of two types of probiotics, namely Water Probiotic (WP) and Gut Probiotic (GP), as well as a control group using LactoBacillus spp.. Probiotics are administered through water and feed at doses of 1 and 3 ppm. The research was carried out for three months (October-December 2024) at the shrimp pond "Farm Umi Azizah and Brother", Tanjungmojo, Kendal Regency. Sampling is carried out six times a week. The results of the analysis using Pearson correlation and linear regression showed that the administration of Bacillus spp. improve water quality stability and approach optimal standards according to KP Regulation No. 75 of 2016. Temperature and salinity have the dominant influence, DO shows the lowest correlation, and GP3 pools produce the best growth. GP1 ponds showed a significant relationship of 94.5% between water quality and shrimp growth.]]>
