In invasive species research, there's a big focus on population and community-level impacts. That appears to be true for NGNT fish, as well. These fish could be having effects on the genetic level, in terms of hybridization with related fish, or on the whole-ecosystem level, such as nutrient cycling of the system. But based on the available studies, we simply don't know.Unlike game fish, which are intentionally stocked into lakes and streams, NGNTs are typically moved by anglers dumping bait buckets after a day of fishing, through contaminated fish stocking, or when aquarium hobbyists release pets in nearby streams.