Reiko is Kimura Tatsuya's pet silver arowana that was named after his love interest of the same name.
History[]
Part I[]
Hot Rod Era Arc[]
When Takamura Mamoru, Aoki Masaru, and Makunouchi Ippo visited Kimura Tatsuya's room, Ippo accidentally fed Reiko Kimura's aspirin, making her stop moving, seemingly dying. However, Reiko later began to move around again, with her owner relieved.
Execution Arc[]
As Kimura's JBC title match against Mashiba Ryō loomed closer, Kimura fed Reiko as he was wondering what he would do once he got close to the champion. When Reiko jumped to get the cricket, the height of Reiko's jump made Kimura get an idea, feeding Reiko again to see the angle of Reiko's jump again. After Kimura lost, he thanked Reiko for giving him the idea for the Dragonfish Blow that let him fight as well as he did.
Part II[]
Seiken Arc[]
Reiko was seen when Kimura and Aoki were talking about how Kimura got carried away when he reacted to the outcome of Mashiba and Sawamura Ryūhei's match.
Scratch Arc[]
Reiko was seen when Kimura and Aoki were talking about Aoki getting revenge on Takamura.
Blind Step Arc[]
Reiko was seen when Kimura had a celebration party at his house with Aoki, Ippo, and Itagaki after winning the first round of the Class A Tournament.
Part III[]
Importance of the Support Role Arc[]
When Reiko jumped, Kimura assumed she wanted food. When Kimura grabbed a container of crickets for her, she started splashing water in excitement, getting water on the thirsty Kimura. In response, Kimura tried drinking water out of her fish tank until Ippo stopped him, dropping crickets everywhere.