Underutilized seafood by-products bear considerable potential to reduce economically and environmentally unsustainable fish meal and oil use in aquaculture feeds. The current study investigated the suitability of brown shrimp, Crangon crangon, processing remains (BSPR) as feed ingredient for Pacific Whiteleg shrimp, Litopenaeus vannamei. Two controlled feeding trials with juvenile L. vannamei were conducted to determine growth performance, feed utilization, digestive enzyme activities, and haematological parameters. In a preliminary feeding trial, shrimp showed best weight gain with diets replacing 50% of fishmeal with BSPR when compared to the control (p = 0.003). Muscle tissue (moisture, protein, lipid) and digestive enzyme activities were not affected by diet. The daily molting ratio increased significantly (p = 0.005) with high BSPR inclusion levels and a higher molting synchronicity was observed. The second feeding trial with diets representing 0, 20, 40, 60, 80, and 100% replacement of fishmeal with BSPR showed significantly enhanced growth when replacement exceeded 60%. Concomitantly, feed conversion ratios improved by up to 37% when BSPR was included in higher proportions than fishmeal. Shrimp haematology (protein, haemocyanin, phenoloxidase activity, prophenoloxidase activity) was not affected by dietary treatment, suggesting good health and nutritional status of the shrimp. Brown shrimp processing remains are a nutritive valuable, growth promoting feed ingredient for L. vannamei.