At the age of 13, Oyogu decided to learn Fishman Karate and Fishman Jujutsu from the Fishman Dojo located on Fishman Island. The majority of the time, Oyogu couldn't complete a task, or perform Fishman Karate for the most part. However, at the age of 16, Oyogu became more confident in himself and trained nonstop for days. Eventually, he was capable of performing both variations, but he still wasn't anywhere near to being a master of it. At the age of 17, Oyogu began his journey and traveled to East Blue. There, he was raided by a pirate crew, and he fended them off easily.