The dusky frillgoby (Bathygobius fuscus), also known as the brown frillfin, is a species of goby which is found in the Indo-Pacific region from the South Africa north to the Red Sea and east as far as Tonga, south to Australia and north to Japan. It is a mainly coastal speciesbut it has an amphidromous life cycle and it occurs in estuaries and will move into in freshwater streams. In estuarine areas it is found mainly