Chapter 3 discusses a number of invasive alien fish species; such as Chitala ornata; Pterygoplichthys spp.; Pangasius spp.; and Asian carp; among others; that are introduced to nonnative regions; how they affect the native ecosystem; and mitigation strategies used to control their populations. This chapter also focuses on their nutritive profile when processed as fishmeal or fish oil replacement as well as their potential and actual use; benefits; and disadvantages when used as an animal feed; specifically as an aquafeed.