Fig. 2. Model bottle method used in field experiments to evoke and record motor and acoustic behaviors produced by Chaetodon multicinctus. One or two fish (one shown) were collected by divers, placed in a glass jar and introduced into the territory of a conspecific pair. A hydrophone (H) placed near the bottle detected sounds that were recorded on the audio channel of an underwater video camera (VC). The resident pair quickly discovered the intruders and initiated agonistic acoustic behaviors.