Gemma...... This goes along with you never know what you are going to get..... Sarah and I bought our first Koi on inauguration day in January from a local fish farm, they were big, but they had lived for the previous 6 months in a galvanized stock tank with a bunch of channel catfish..... They were in pitiful shape, shredded fins, itch all over them, skinny, over this summer they have filled out, their colors have intensived and they are beautiful now and huge, so in March we bought four Butterfly Koi from our local high school, three of them have done pretty good as far as coloring, but I have one that was a white body with bright yellow head and bright yellow spots on its body, but now it has a pale yellow head and a completely white body, it has grown and it is healthy, but lost its color, and lastly we bought a Koi in March, she was about 5 inches long, pretty coloring, supposed to be a butterfly..... I paid a God Awful price for this fish, I am ashamed to say, so I won't. But as she grew she was a little short dumpy thing, was growing and holding her color but not growing in length, that being said I was disappointed.... But within the last month she has lengthen and her fins are turning white, don't know where the white came from but every day they are getting brighter..... And is turning into quite an unique fish. So my point is you never know what you are going to get..... If you are feeding them the right food and your water is good, it has to be genetic, you never know how they will turn out