Sampling tissue on fish is usually carried out with the lethal collection of organic material (i.e. liver, brain, muscle...). Analysis of the fatty acid (FA) composition of fish tissue can provide information about nutritional quality, trophic behavior and is widespread in aquaculture research. Here we provide insight on an innovative non-lethal sampling method for FA analysis in European sea bass (Dicentrarchus labrax) juveniles. We performed six replicates of subcutaneous white muscle biopsy (between 1.5 and 15mg) on six individuals. White muscle was also collected on the same individuals following a classical lethal sampling method to be compared with biopsy sampling. FA of both reserve lipids (RL) and membrane lipids (ML) were analyzed. FA profiles of ML were similar in biopsy and the classical sampling, and showed repeatability among biopsy samples collected on the same individual. RL FA profiles showed high variability between biopsy samples taken on the same individual compared to ML. Lipid droplets located between white muscle and the fish skin could explain this difference. This sampling method could then prevent sacrifice of fish by using small quantities of tissue for FA analysis and be applied in various research areas. Special caution has to be taken during the sampling to avoid lipid droplets near the skin. Further investigation should be considered to assess the later effects of the biopsy on fish.