Yea, invasive to the US. They are established and are not going anywhere now. The US even completely poisoned a few lakes in an attempt to eliminate them in the wild. Naturallly, Singapore is a native habitat. If you are unsure about if it was a snakehead or a bichir, then I would not worry about if its a snakehead. Since it is native, I would also not worry about environmental impacts. They get a bad reputation in America but there is nothing to keep them in check here. They are an elite predator that has found a comfortable home in the states