Juvenile French angelfish have a black body with white/yellow bands, while adults have a dark gray body, a blue face, and gold-tipped scales. The babies can form “cleaning stations” on reefs, where they nip at the parasites on other fish, while adults mostly feed on sponges.
French angelfish are monogamous, meaning that they stay in pairs until separated by death.
…I guess you could say that sea hares are polygamous, then, since they have multiple mates. They’re just too loving.