I accidentally bought a Koi last year thinking she was a cute white goldfish. Decided to keep her once I realized. Her name is Kai. She lives in the pool with my goldfish. I have had her a year. She is such a sweet and gentle Koi. She does not bother the goldfish and they all eat the same foods. Problem is - she is now like a foot long and growing quickly!
I would love to keep her... but can she comfortably live in a 500 gallon pool with a group of goldies? If she gets any bigger than this - IDK!
Here's her Pic when I got her with the two goldfish at Petco in a 10 gallon tank... and then now!