Disease that often develops in aquaculture is one of them is red spot disease. This disease is often called Motile Aeromonas Septicemia (MAS) caused by Aeromonas hydrophila. Natural ingredients that can be used as prevention and treatment of fish diseases are kersen leaf plant (Muntingia calabura L) which is antibacterial and antimicrobial. This research was conducted in December 2018-February …