The type of koi you try to train can matter too. "Make sure you have at least one friendly variety such as Chagoi, Soragoi, Ogon or Karashi," Kodama advises. "Feed them Manda Fu, a special food ...

As the name implies, it's an outdoor pond populated by koi fish, a colorful, domesticated carp that adapts well to a variety of spaces. Originally domesticated in China, these beautiful fish ...