Akira's on the other hand is a koi fish that is shown to be swimming upwards, symbolizing how Akira is gradually building up his reputation and status within the Tojo Clan.

Source: https://gamerant.com/yakuza-facts-fans-should-know-about-ichiban/

It manages to not only do all of that effectively, but it manages to weave in the Omi Alliance, the Tojo clan, the Yakuza dissolution, and so much more.

Source: https://gamerant.com/like-dragon-gaiden-ending-explained-kiryu-joryu-identity-children-ugly-cry/