They "can go for as much as $300,000"??? I grew up in the Philippines, out there, everyone has one. They didn't cost a lot, but I am sure there are rare and larger varieties that do. There are rivers in parks in Singapore that have huge Arowana's.
Yes, they can go for $300K or more -- I've seen them sell for more.
But, that's a little like saying a bottle of wine can sell for $10,000 or more. True, if you've got Rothschild, but I'm over here drinking a bottle I bought because the label looked cool.
Unless you're talking high grade, big sized, rare strain and colours, they ain't selling for $300K, and I doubt the lady cooked an expensive fish.
Although, that said, if my wife (when did I get married?) cooked one of my pets, the price tag would be the least of my worries....