Hi Dinh, Yep, I'm pretty sure that Hawaii is first. I had this discussion with Steve H on NI and provided the dates back then, maybe he kept them and saved the info ( I still have a problem getting on koi Bito unless I use an old lap top with the 'magic cookies!" ;

so I can't respond easily. I will get to my laptop with hard dates tonight
But here is a big picture view that might help your thinking and time this together or at least expand your perspective.
Koi keeping came to America from Japan, specifically from Hiroshima and not what we usually associate with early modern koi years - I.E. Niigata.
The reason for this is Hiroshima, after the war was a place of departure ( for obvious reasons) and many workers left to go to Hawaii and eventually Southern California. As a result the natural export chain from Hiroshima ( and Konishi farm) was established. In the very early days fish were still coming from Niigata to the mountain carp farms because the low land farms were gone. The breeders there were as much grow out farms as much as producers - but production was started to key points in the world- Hawaii and Southern California being natural as the language and cultural barriers were nil. So the first beach head was Hawaii. Then California. And the natural distributors were Japanese Americans. Later, the triad in Japan created the Japanese economic miracle- a defeated country rose with cooperation been government, business and banking. This mind set became all consuming. The dept of agriculture got in bed with the breeders and the business and banking produced fuel for land. In this process ZNA saw its purpose over seas- spread the culture, spread the brotherhood and spread the business. ZNA became a type of triad for koi kichi, proud wealthy Japanese representatives and breeders/dealers. These were also the days of innocence however and little corruption had yet taken place. In the spirit of Japanese cultural expansion, the koi came to Hawaii and then the east coast. The wealthy hobbyists soon followed . This is the point where we see clubs formed by the Japanese American community. It takes then a few more steps for the cultural aspect to become ‘amateur-ized’ again, as it originally was in Japan once upon a time. But along the road there were already conflicts/turf wars between high minded wealthy Japanese amateurs and the dealers that felt threatened. In many cases, the amateurs came with their own dealers in tow as part of ‘spreading of the hobby’ and this, as you can imagine, went over like a lead balloon. Additionally, although ‘men from Japan’ has instant ‘street cred’ among the gaigin, not so with the Japanese Americans and other Americans who felt their Japanese ZNA brothers would always treat them like ‘child students’ and vessels of Beppu Japan. So many remained focused on the politics, on threats to their own business plans and on the heavy handedness of a Japanese run organization with plans of its own. Others realized that the distance and language barrier allowed for a focus in the simple message of friendship through scales and the enjoyment of Japanese art in nature.