Koi and oscar

Question
Can you put both fish in a tank together?  

Answer
NO...absolutely not. Koi are cold water fish...not that they mind warmer water, but do much better in cool water. The oscar will eat anything it can get its mouth around. And if it can't eat it, it will harrass it. Koi is a type of goldfish...which, in turn, is a great snack for oscars.