First of all, it must be clear that there will be no prosperity if gangs donate fish one by one. Only by wrapping up and donating will there be prosperity, so remember not to donate one by one in the future.
Number of herring plus single donation minus 1 prosperity. Every Monday at eight o'clock, the number of times the guild exchanges gems will be cleared, and so will the shops that have also been upgraded, so don't upgrade the shops on Monday, but wait until Thursday and Friday.