The Swan Mussel is a freshwater ‘bivalve’ mussel which means it has a soft body that is enclosed in two hinged shells. It can be found in lakes, canals and slow-flowing rivers. It buries itself in silt or mud as deep as twenty metres and it extends two ‘siphons’ which are tube-like organs that can take water in and squirt water out.
The Swan Mussel has an oval-shaped shell which is usually a brown colour with lots of darker or lighter brown curved lines. It can sometimes be a yellow-brown or an olive-brown colour. The inside of the shell is pearly white and the soft body inside is a rosy orange colour. The Swan Mussel has a large muscular foot which the mussel uses to burrow into the sand and to move along the surface. If it gets disturbed, it can quickly close both shells tightly shut.
The larvae of the Swan Mussel hatch inside the mussel during winter, but they are not released till the following spring. When they are released, they have sticky thread-like strings trailing behind them and the larvae use these strings so they can attach themselves onto fish. The larvae suck blood out of fish for a while and then eventually drop to the bottom of the water to develop into adult Swan Mussels.