Red dragon fruit peel is a natural material with antibacterial potential against fish diseases. This study was conducted from July 2024 to June 2025 at the Laboratory of Fish Parasites and Diseases, Faculty of Fisheries and Marine Sciences, Universitas Riau. The aim was to determine the histopathology of gills and kidneys in striped catfish (Pangasionodon hypophthalmus) immersed in red dragon f…