I am in my high school aquaculture program and my teacher is going to give me a Koi fish. I know they should be raised in ponds but i cannot do that where i live. i love the koi fish and they are really beautiful. i just don’t know what i need to keep it happy. the space i have is limited though i know they can grow to be quite big. is there a way to slow down their growth without harming them? what size tank should keep the 1 koi fish happy and at the moment, it is about 2.5 inches long. thank you for the help.