The fish was lidted as appendix one in the first CITES convention in 1974. The American Lacey Act (which pre-dates CITES by about 70 years) prohibits importation and possession of highly endangered species. The Asian arowanas in the trade are bred on fish-farms for colour/pattern/etc, and are produced by the thousands. The problem for the US comes in the fact that CITES designation is based on wild populations, not captive-produced ones, so until someone reclaims some wild habitat and helps repopulate it, or until an amendment is made to the Lacey Act, the fish will remain banned in the USA.
A note on the Asian aros (prices based on 6"-12" juveniles, adults are 2-5 times as much, depending on how well their colour and body-shape develop)....
B-Grade greens (wild-type colouration) and yellow tails sell for as little as $500 each
A-Grade chili-reds, red-tail golds, and other mid-range colours sell for about $1200-$3000
AA-Grade and AAA-Grade sapphire blues, gold-heads, etc sell for about $3500-$7500 each
AA-Grade and AAA-Grade violet fusions, blue-base blood reds, and other top colours start at about $9000 and can sell for $50,000 or more.