In agonistic interactions with conspecifics, skunk loaches (Botia horae) typically exhibit lateral displays, attacks, and produce a sound (a “click”). Four experiments were conducted to determine the functional significance of the click sound. Behaviors of resident fish were monitored while characteristics of their shelter and the size or type of intruder fish introduced were varied. Manipulations in the four experiments involved: 1) the configuration of the available shelter; 2) the size or recent history of intruder fish; 3) playbacks of “click” sounds or aquarium noise; or 4) muting of resident fish. Lateral displays, attacks, and sounds produced by residents were monitored, and the responses of residents were analyzed in terms of the functional significance of “click” sounds to juvenile skunk loaches.