Abstract the objective of the study was to figure out the effect of jatropha curcas leaf extract on the hatching rate and prevalence of fungal infection on goldfish eggs (c. auratus). the research was conducted at marine fish hatchery laboratory, marine and fisheries faculty, syiah kuala university on february 2018. the research used completely randomized design with seven treatment of extract concentration, namely ; 0, 20, 40, 60, 80, 100 and 120 ppm with three replications. the result of ansira showed that j. curcas leaf extract gave the significant effect on hatching rate and prevalence of fugal infection on goldfish eggs (p