The aim of the present study was to investigate the effects of replacing fish oil by different microalgae products on the growth performance and fatty acid composition of gilthead sea bream (0.02 +/- 0.00 g) during 90 days of post larvae and weaning period. Four diets were evaluated: control diet was exclusively based on fishoil; SBAE diet included the commercial product SBAE (R), which consists of four microalgae: Tetraselmissuecica, Isochrysis sp., Nannochloropsisoculata and Phaeodactylumtricornutum; Algamac diet included the commercial product Algamac 3050, which consists solely of the microalgae Schizocthytrium sp., and Mix diet that consisted of a mixture of both commercial products in equal amounts, SBAE (R) and Algamac (R). At the end of the feeding trial, the highest weight gain was obtained in Control (1.34 +/- 0.00 g) and Mix (1.34 +/- 0.03 g) groups(P<0.05). The highest survival rates were found in Control and Mix diet groups, whereas the lowest was found in SBAE diet group. Experimental diets showed significant effects on the fatty acid composition of larvae. The total long-chainn-3 polyunsaturated fatty acid (LC-PUFA), eicosapentaenoic acid and docosahexaenoic acid levels were increased with inclusion of microalgae products. Based on the results of growth performance and fatty acid composition, fishoil substitution by a blend of equal amounts of microalgae products SBAE (R) and Algamac (R) 3050 seems to be promising in weaning diets for gilthead sea bream larvae.