This is the sort of nonsense I'm up against.
These were being sold as 剑鱼 (jiàn yú) which translates as 'swordfish, which they clearly aren't.
They're plain old catfish! Specifically channel catfish, Ictalurus punctatus, America's most fished species. They have been introduced around the world, including to China. However, in many countries, they are classified as an unwelcome invasive species.
$3 USD / 500g.
We do get real swordfish to which I will return.