This work aimed to determine whether a minimum provision of marine oil in practical diets for Litopenaeus vannamei is required when replacing fish meal (FM) by soy protein concentrate (SPC). The study consisted of three growth experiments conducted in 500-L tanks with 70 shrimp m À2 . In experiment #1, FM was progressively replaced by SPC as fish oil (FO) levels increased with a consistent input of whole squid meal (WSM). In experiment #2, FM was replaced by SPC under two levels of FO (10 or 20 g kg À1 ) without the presence of a feeding effector. In experiment #3, three dietary levels of krill meal (KRL) and WSM (5, 10 and 20 g kg À1 ) were included in a basal diet containing SPC and low levels of FM. Results showed that under a clear-water condition, the dietary levels of FO in practical diets for L. vannamei have a significant impact on the amount of FM that can be replaced by SPC. As much as 31% replacement of FM/SPC was possible with 20 g kg À1 FO. Whenever dietary fat was adjusted by using FO as a lipid source, complete replacement of FM by SPC was achieved with no negative effect on shrimp growth.