Lambak fish (Labiobarbus ocellatus, Heckel 1843) is a species of freshwater fish belonging to the Cyprinidae family and is only found in the waters of Sumatra and Malaysia. Knowledge of sexual dimorphism is very important in the study of fish breeding. This research aimed to analyze the sexual dimorphism and reproductive biology of L. ocellatus from the Kelekar River, Ogan Ilir Regency, South S…