Most catfish farmers do not make efforts to manage water quality. This causes high organic matter. Therefore, water management is carried out through the Recirculating Aquaculture System (RAS). Continuous use of water in the RAS system causes filter performance to decrease, so technological improvements are needed with the addition of probiotics. The research was conducted on 22 February – 23 March 2021 at the Chemistry and Analysis Laboratory, Faculty of Fisheries and Marine, Universitas Airlangga to determine the influence of probiotic additions on the RAS system total organic matter and the survival rate of catfish.The study was conducted experimentally using RAL by adding different doses of probiotics, namely P0 (Control), P1 (0.5 ml/L), P2 (1 ml/L), P3 (1.5 ml/L) and P4 (2 ml/L ) with four replays. Data analysis using ANOVA and DMRT showed that the addition of probiotics in the RAS system has an effect (p<0.05) on total organic matter and survival rate. Organic matter was highest at P2 (46.89 mg/L) and lowest at P2 (34.07 mg/L). Survival rates were highest at P2 (85%) and lowest at P0 (71.25%).