I have bought koi online from 2 different dealers...champkoi and JKO. I have to admit, their photography was very good. The koi looked just as expected..and on a few occasions, even better. The photo can give you a good idea of pattern, shape and thickness...but not height. Also does not capture sheen at all. My local dealers are good...but carry mostly 10 inch and under koi. If I want a 16+inch koi...I have little choice but to use photography and the internet.
I also want to add...I've missed flaws in person, that I would have seen in a photo. I have a shiro utsuri with a crooked tail that i missed. If the fish is active in the bowl and splashing around...it can slip past you very easily.
Here is that fish...on the left, the day I bought it...easy to miss the crooked tail at 4 inches. On the right..easy to see at 9 inches. I had other pics of 4inches that showed the crooked tail..didn't see it at all!!!
A friend might use her as a breeder eventually. Still a cute little thing
