Piranha are NOT illegal in NJ.
they are indeed illegal to land at JFK and /or Laguardia Airports in NY and cannot be sold within the 5 borough's of NYC. In NJ they are still okay to land and be sold anywhere.
Piranha are however banned for collection and export from Colombia & Venezuela. This has been the case for about 2 years now at this point. So this now limits us to piranha species from Brazil and Peru for the most part. so off the top of my head this will eliminate wild cariba, mento, denticulata and a few others from that region of the world. included in the same ban would be wild Cichla species from Colombia, Venezuela, and also Peru. Oscars, yep oscars, are also banned for export from Peru