Assuming the biggest hit is coming from the restaurant industry I would pass a law -- if it weren't already on the books -- forcing them to disclose they use the Chinese catfish. This wouldn't be some fine print buried at the bottom of the menu but a big, glossy sign right as you go into the establishment.
Give consumers the information and let decide if it's worth paying more to employ American workers.
I guess the extreme answer are tariffs and protectionist trade but I'm not a huge fan of that.