This research aims to determine the influence and optimal concentration of papaya leaf extract for treating Saprolegnia sp fungal infection in gourami fish seeds. The method employed was a Completely Randomized Design (CRD) with 5 treatments and 3 replications, namely treatment P0: without papaya leaf extract (0 gr/L), treatment P1: papaya leaf extract concentration of 0.1 gr/L, P2 (0.2 gr/L), …