Aquacultural production is increasing in most parts of the world, establishing new and rapidly growing markets for various oil products. One of the more interesting nutritional requirements for aquatic animals is lecithin or phosphatidylcholine. In this paper, lecithin in aquaculture is reviewed with emphasis on freshwater fish and crayfish. Further, new data on use of lecithin and two soy protein concentrates in diets fed to coho and Atlantic salmon are presented. Juvenile coho and Atlantic salmon were fed either solvent‐extracted soybean meal (SBM) or Promocalf® at 30% of the diet, Promoveal® at 10, 20 or 30% of the diet, or one of three new lecithin products at a constant level of 3% of the diet. Juvenile coho salmon fed SBM, Promocalf®, or Promoveal® at 30% of the diet exhibited depressed weight gain and an elevated feed conversion ratio (FCR) compared to fish fed a positive control diet. Fish fed 10 or 20% Promoveal® had similar weight gain and FCR compared to fish fed the control diet. Coho salmon fed either of the three lecithin products (Aqualipid®, Blendmax®, or Centrol®) had similar weight gains and FCR values compared to fish fed the control diet. Whole‐body proximate components were not as responsive to dietary treatments as weight gain and FCR data. Juvenile Atlantic salmon exhibited depressed weight gain only when fed 30% Promocalf® and all three lecithin products. Further, whole‐body crude protein concentrations in fish fed the three lecithin products were depressed.