Juvenile Japanese flounder were sourced from a commercial hatchery, Matsumoto Suisan, Miyazaki, Japan and was acclimatized for 2 weeks in a 500 l tank and fed a commercial feed (Higashimaru Foods, Kagoshima, Japan). The growth experiment was conducted at a flow-through sea water facility of the Kamoike Marine Production Laboratory, Faculty of Fisheries, Kagoshima University, Japan. Japanese flounder juveniles (average initial body weight of 1.01 ± 0.02 g) were stocked in 100 l tank (80 l water volume) at 15 fish tank− 1, with each treatment having three replicates. All fish were fed to apparent satiation with the designated diets twice daily (8:00 and 16:00 h). Uneaten diets were collected, freeze dried and weighed for corrected feed intake calculation. Periodic samplings of every 2 weeks were conducted to monitor instantaneous growth rate and mortality in the tanks. The water flow (seawater) to the tanks was 1.5 l min− 1 and a photoperiod of 12 h light:12 h dark was maintained throughout the experiment. In the duration of the feeding trial, monitored water parameters were; temperature (16º ± 1.6 °C), pH (7.8 ± 0.3) and salinity (32.8 ± 0.9‰).