Once a simple food fish, koi have transformed into living jewels, with some fetching sky-high prices in the global luxury market. Here's how this happened. In the world of high-end pets, few creatures ...

If you take a walk around San Francisco, it won’t take long before you see a koi fish. Not a real one, of course, although the bright orange-and-white graffiti art has the fluidity of a real fish ...

A dozen koi fish poke their faces up to the pond’s surface, hoping for a bite to eat. They’re smarter and more social than most would give them credit for, and they recognize horticulturists Mark ...