Ichirō Yamaguchi (山口一郎) is the vocalist, guitarist, composer, songwriter, and founder of the band sakanaction, following a transition with his previous group Dutchman.

In an interview with The Japan Times, Yamaguchi described his influence with the fishes in the sea:

I’m influenced by freshwater fish. They live in cold water, sometimes underneath the rocks, and they continue swimming against a strong current. I would like to live like them; always swimming against the flow.