Invasive alien fish species (IAFS) are non-native fish species introduced into marine or freshwater systems beyond their native distribution range. IAFS are often dispersed through anthropogenic activities. Their introduction has drastically modified ecosystems and threatens the extinction of native species. Harvesting IAFS for utilization as an aquafeed ingredient is attractive because it is cheaper than other mitigation strategies and revitalizes the commercial fishing industry. As the aquafeed industry is continuously confronted with rising costs amid the heightened pressure on the availability of feed ingredients, IAFS may likely fill in the shortages and demands without competing for human consumption. Fishmeal derived from IAFS could be a suitable alternative as it mirrors traditional/standard fishmeal and is not likely to possess the undesirable characteristics of plant- or other animal-based alternatives. Using IAFS as aquafeed is a viable short-term approach, but it is still limited due to the lack of information on IAFS fishmeal quality. This chapter discusses a number of invasive alien fish species, such as Chitala ornata, Pterygoplichthys spp., Pangasius spp., and Asian carps, among others, that are introduced to non-native regions, how they affect the native ecosystems, and mitigation strategies used to control their population. 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.