He admitted that he sold illegally imported arowana, which are native to Southeast Asia and protected by the Endangered Species Act, in 2016. Arowana are the most expensive freshwater fish in the world. Nguyen also admitted to selling snakeheads in 2019 in violation of Pennsylvania law. Snakeheads, also native to Asia, are not endangered but are an invasive, aggressive species that many states, including Pennsylvania, have restricted because of the damage they have done to native fish. As part of Nguyen's plea, he accepted responsibility for falsifying documents related to a snakehead shipment.