The research was conducted from 1st October - 27th December at Fish Hatchery and Breeding Laboratory, Fishery and Marine Science Faculty of Riau University. The aim of this research was to evaluate the effect of adding Ascorbyl Phosphate Magnesium (APM) on gonad maturation of Sheatfish (Ompok rhadinurus). The broodstock were reared in 12 (70 x 70 x 100 cm3) cages (5 fishes/cage), placed in…