Global production of farm-raised shrimp has significantly increased in recent years leading to oversupply and unfavorable market shrimp prices. As the industry aims to adapt, seeking production and economic efficiency, feeds become a crucial element for cost rationalization. This study determined the minimum dietary level of fish meal (FML) and krill meal (KRM) and their mix ratio to elicit feed intake and growth performance in Penaeus vannamei. Ten diets were formulated with graded FML (90, 60, 30 g kg-1) in combination with 15, 30, and 45 g kg-1 KRM, and a control diet with 120 g kg-1 FML. Shrimp (1.28 ± 0.08 g body weight, BW) were stocked in seventy 1-m3 tanks (135 animals m-2) and after 88 days their growth performance was determined. Feed preference was assessed through two-by-two comparisons in twenty 0.5-m3 tanks over four weeks. No significant differences in survival (93.9 ± 4.5%), gained yield
(1,235 ± 92 g m-2), and feed conversion ratio (1.47 ± 0.09) were observed. Diets with 60 g kg-1 FML led to faster growth and higher feed intake than 30, 90 and 120 g kg-1 FML. Shrimp on 30 g kg-1 FML diets had the lowest BW, especially with 30-15 (FML-KRM) and 30-30 diets. Diets with 90 g kg-1 FML outperformed 30 g kg-1 FML. The control diet had higher body weight than diets 30-15 and 30-30, showing similar results to other diets except 60-15. Feed preference was influenced by KRM inclusion, with 15 g kg-1 KRM resulting in higher apparent feed intake than 30 and 45 g kg-1. The findings indicate that higher levels of KRM and FML in combination do not contribute to greater feeding stimuli or enhanced growth performance. These results enable the reduction of their utilization, from 120 to 60 g kg-1 FML and from 45 to 15 g kg-1 KRM, while still stimulating feed intake and growth performance in whiteleg shrimp.