Sound production in the cichlid Tilapia mossambica Peters

Aquarium‐bred adult and juvenile Tilapia mossambica Peters can produce sounds ofvarying frequency, duration and intensity. However, minor environmental disturbancesmay cause the fish to fall silent for long periods. The sounds produced by excited feedingfishes are different from those produced by territorial males and from those emitted by fryswimming in school formation. The frequency of the sounds recorded varied from about1–16 kHz; no data are available on frequencies lower than 1 kHz. The sound producingmechanism consists of a single ventral and two dorsal pharyngeals located in the buccalcavity and provided with numerous small teeth. These teeth have a specially modifieddistal surface area which is already evident in younger fish. Young Tilapia, including3‐week old fry, are able to emit sounds as soon as a sufficient number of teeth havedeveloped in the pharyngeal region.