Question: when does zac find out they are mermaids

title: List of Mako: Island of Secrets episodes
text: Zac struggles to come to terms with the revelation that he is a real merman who was given up for adoption by Mimmi 's mother . He isolates himself from everyone else and refuses to accept Mimmi as his sister . When a couple of jerks show up and ridicule Zac by calling him a quitter , Zac becomes very angry and begins recklessly using his powers against them . Mimmi and Evie manage to calm him down before he goes too far by reminding him that , unlike Mimmi , he has two parents who love him . Afterwards , Zac talks to his parents who tell him about how they found him and adopted him as a baby . The next day , Zac finally accepts Mimmi as his sister .