What does it mean to look for blue koi fish?

The motivation to pursue good things, good luck and happiness.

Looking for blue koi fish is an online buzzword, which originated from a segment in the Japanese animation Girl of Light. In this clip, the protagonists Youer and Unique have a lucky draw, and the prize is a blue koi fish. But in fact, the color of koi fish is very rare, so it has become a symbol of luck and rarity. Looking for blue koi fish means pursuing luck or something rare. It can be used to describe the mentality of hoping for special opportunities or rare items, and it can also be used to express expectations and blessings for good luck.