We estimated the digestibility and growth rate of juvenile olive flounder (Paralichthys olivaceus) on three diets: raw fish-based moist pellets, moist pellets, and extruded pellets. The diets were created using commercially available methods, and a basic formulated powder. A reference diet was used to compare feed digestibility and the fish growth rate achieved using the experimental diets. The apparent digestibility coefficients (ADCs) of protein for raw fish-based moist pellets and moist pellets were significantly higher (P<0.05) than those for extruded pellets and the reference diet. The ADCs of nitrogen-free extracts (NFE) of extruded pellets and moist pellets were significantly higher (P<0.05) than those for raw fish-based moist pellets and the reference diet. Fish that were fed with the raw fish-based moist pellets showed the greatest weight gain (452.4%), which was not significantly different from that of fish fed with extruded pellets (414.4%; P>0.05). These results indicate that the higher protein efficiency in fish fed with extruded pellets can result in good growth performance within flounder culture systems.