Manipulation effects of jack mackerel meal (JMM) in the lowfish meal (FM) diets substituting 50% FM with meat meal(MM) on growth performance of olive flounder and economicanalysis were determined. Seven experimental diets were cre-ated. The control (Con) diet contained 60% FM. In the otherdiets, 50% of the FM level used for the Con diet was substitutedwith MM, and then graded levels (0, 10, 20, 30, 40, and 50%) ofJMM were included at the expense of FM, named the MJ0,MJ10, MJ20, MJ30, MJ40, and MJ50 diets, respectively. Theexperimental diets were distributed to triplicate groups of fish.A total of 525 fish was divided into 21 flow-through tanks. Fishwere hand-fed to apparent satiation for 8 weeks. Weight gain,specific growth rate (SGR), and feed consumption of fish fedthe Con diet were comparable with fish fed the MJ20, MJ30,MJ40, and MJ50 diets. Weight gain, SGR, and feed consumptionof fish linearly improved with JMM inclusion levels in the lowFM diets replacing 50% FM with MM.