Banded Humbug

• Each group has a strict hierarchy by size, and individuals regulate their own growth so as not to challenge the one immediately above them.
• It changes sex: all are born female and the dominant individuals become males, a case of protogynous hermaphroditism.
• The coral it lives in benefits from the association: the movement of the shoal among the branches improves water circulation and the oxygenation of the colony.
• It lives tied to a single colony of branching coral, above all of the genus Acropora or Pocillopora, and does not stray from it: the colony is at once its refuge and its territory.
• Groups keep a strict size-based hierarchy, and it is a protogynous hermaphrodite: if the dominant male disappears, the largest female changes sex and takes his place.
• By hiding among the coral's branches it brushes against the polyps and increases the circulation of water between them, which improves their oxygenation. The relationship benefits both.
• It produces audible clicks during courtship and in defence of its territory.
• Its dependence on branching coral makes it especially vulnerable to bleaching: when the colony dies, the group disappears with it.

Skeleton type

Vertebrate - internal bony skeleton (fish)

Habitat & environment

Branching coral colonies in shallow Indo-Pacific lagoons and reefs

Sources consulted: FishBase (Froese & Pauly, eds.); Lista Roja de la UICN; Australian Institute of Marine Science