I should have specified the list is meant to focus on compatibility issues long-term, not short-term. Yes, baby koi are fine but adults are absolutely not. I have witnessed several accounts of adult koi attacking the fancies but not the singletails (obviously).I would have to disagree with the koi being incompatable. I have two orandas that co-exist with several baby koi and they get along just fine. The key is size of the koi as they will outgrow then eventually outcompete the orandas, but the koi are a very docile fish and don't harass them at all. When the koi reach a certain size, it i time for a pond anyways.........