Pronounce koi as it would be in Japanese: ko-i.
That word has more meanings than just "ornamental carp".
On a different note, I've been rereading the quest and I noticed two things that are concerning.
First, I think we can confirm Nothing involvement in that strange letter we received earlier, which raises questions about who sent it and for what purpose.
Second, the Dragonfly are fucked, because Shinji Wanli told their Clan Champion about Copy Moto and yet that information wasn't passed on to the Dragon or its bearer allowed to make her case to the Dragon in person. And that after three months of making every possible effort to gain passage, which speaks to the sincerity of both message and messenger.
EDIT: Another thought occurred to me, this one regarding the cuisine of the Dragon. Namely, that they must have goat milk, which can be turned into things like cheese, butter and yogurt. They might even, on special occasions, have ice cream. Sosuke might find those less off-putting than he did the goat meat.