Oreochromis niloticus is a fish that is very popular with the people of Indonesia, but in its cultivation it often experiences problems caused by Streptococcus agalactiae. This study was conducted from May 2024 to January 2025 at the Laboratory of Parasites and Fish Diseases, Faculty of Fisheries and Marine Sciences, University of Riau and the Bukit Tinggi Veterinary. This study aims to analyze…