Hooded Oyster

Found in dense colonies, over shallow, sub-tidal areas, cemented to breathing roots, and trunks of mangrove trees, harbour walls, and underwater structures, such as pier pilings.

Most Bivalves are permanently anchored in fissures or depressions in the rock surface of the reef, some may become covered in algae and other marine life.
Other Bivalves swim free, either by a well developed foot or propelled along by a jet of water from their mantle cavity.