Behaviors in agonistic interaction of the butterflyfish ( Chaetodon lunulatus )

Abstract

The butterflyfish (Chaetodon lunulatus) forms heterosexual pair bonds. Each pair defends a feeding territory against conspecifics. In the field, I observed the agonistic interactions related to territoriality, and recognized nine behavioral patterns: staring, parallel swimming, rushing, tail-up display, chasing, fleeing, encircling, TT-fighting (two-piled-tops fighting), and attacking. Almost all interactions were conventional fighting in which attacking seldom occurred. In rare cases, interactions escalated to TT-fighting. In these cases, attacks were frequent, and outcomes were significant (e.g., territorial takeover and serious injuries).