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 ...

We are surrounded by non-native plants and animals from dandelions to snakeheads. But the lowly carp, found in almost all our waterways, has perhaps the strangest story. The common carp or Cyprinus ...