Rivers, streams and billabongs of north and eastern Australia invariably contain some form of Freshwater Mussel. The animal is protected by two identical shells hinged together, generally dark brown or black on the outside, 'mother-of-pearl' on the inside. Although usually 5 – 10cm long, they can sometimes be up to 20cm. In still water, Freshwater Mussels may leave a 'track' through the soft sand or mud bottom, at the end of which may be found a small mound covering the shellfish. They also occur amongst water-weeds and reeds. Can you see the mussel in the above photo on . . .