i just looked at the black spot on the fish that someone posted a picture of and figured it was about 1/2" diameter. i don't think the specific fish matters so much as the fact that it can be done and is done. it would make it very difficult to raise a GC if you are competing with others who are doing cosmetic surgery on theirs.
i have some domestic koi, all very friendly. i used to have some kohaku, not show quality by any means, but identifiable as kohaku and again all had good personalitys. i killed them by following the advice of an "expert" on the internet.
i intend to put in a "nice" koi pond, but there is a lot i don't know about koi, especially "nice" koi. it will be a big investment for me and i want to figure out where i am going with this hobby.
where do my questions come from? some directly from this board. someone posted about buying a GC. i did not know it was done and my first impression was that it was wrong. from what i have read here, i was mistaken, it is done more often than not.
i talked to a neighbor who also has koi. he told me that not only are GCs bought from a dealer who raises them and brings them to a show, but MANY are cosmetically altered. so i asked about that and i am still not clear on it, although i am certain there are those who read this board who can give an authoritative answer.
then someone brings up the bonsai nisai vs. tosai question and i have no idea what they are talking about. at first i thought they were pulling my leg, they still might be, BUT if i want to compete in a koi show that will be my level, for financial reasons. and i will not get a dealer to raise it for me and i will not do cosmetic surgery on it.
in short, i am a novice. i hope my questions give others an opportunity to share their knowledge of the hobby.