Organicreefer,
If there is a federal ban, it must not be being enforced. But if you find info on a federal ban, please forward it to us.
State law varies. They tend to be illegal in states with warmer climates, where it is feared that released pets could impact native species and perhaps become a hazard.
Some states, like New York, well... who knows.
Here is a list on a state by state basis:
http://freshaquarium.miningco.com/pe...org/legal.html
If well fed, they can grow quickly, reaching full size in about a year.
They tend to be nervous and not very good pets, but can be rather pretty.
Regards,
Scott Passe