Red swamp crayfish is one of the most dangerous invasive alien species in Europe. This study investigates the nutritional value of a flash-dried whole meal as a novel possible ingredient in finfish diets. Based on the analysed nutrient composition and digestibility measured in rainbow trout, the flash-dried red swamp crayfish meal results to be a suitable complement or a partial alternative to conventional vegetable and/or animal protein sources in fish diets. Moreover, the high concentration of astaxanthin (a carotenoid with several positive physiological roles) makes it even more attractive also as a natural and functional ingredient for organic aquafeeds.