There are piranha species from Argentina and Uruguay that will withstand winter temps in Louisiana, and other parts of the southern U.S., so banning them, as long as people do ignorant acts like releasing them will be an obvious reaction.
Already up to state legislature (lucky to live in a legal state). I’d have some choice words for anyone who decides to make them nationally illegal.
This type of thing happens often enough in warm areas. I think that as long as people are smart, piranhas can stay legal. Luckily, they cannot survive every state. Then we would have another snakehead problem...
When I saw at different article on this, this was my first reaction as well. If people are releasing them unfortunately it does make sense based on the possible consequences.