Protein and energy requirements of Sparus aurata fingerlings were studied at high and low temperatures. Eight diets containing three protein levels of 40, 45, and 51 percent combined with three lipid levels of 11, 16, and 21 percent and variable carbohydrate content were fed to satiation to populations of 2.1-2.8 g initial weight at 25 degrees or 10-14 degrees. The better performing diets at satiation and those with higher protein content were fed to satiation or under restricted feeding. At high temperatures, Diets 7 and 8, containing 51 percent protein with either 16 or 21 percent lipids, seemed to better support performance when fed to satiation. At low temperatures, Diet 7 also showed the best performance, although not different from the diet with 46 percent protein and 21 percent lipids. When feeding levels were reduced feed efficiencies improved but higher content of protein was necessary for optimum performance.