This review reports some interesting works on the recovery and fractionation by membrane techniques of marine compounds resulting from hydrolysis of fish by-products such as proteins or peptides, lipids or fatty acids, and carbohydrates. Ultrafiltration (UF) appears as the most widely used technique for such applications. It must be noted that only a few works deal with the optimization or the enhancement of processes for the recovery of added value molecules. Indeed, most of works use UF as a convenient and simple tool for solute fractionation, for this reason the influence of operating parameters on membrane separation efficiency is unfortunately seldom considered. When attention is paid in a study to the process development, it is specified in this review.