Another thing is that some ocean habitats aren't technically in the ocean and these are called estuaries, areas when oceans and rivers meet creating a mixture of salt water and freshwater making a different habitat for different types of fish and creatures to live in.[5][6] The ocean is home to organisms as large as whales and as small as microscopic marine organisms such as phytoplankton. However, the vast majority of ocean life that humans are exposed to is simple saltwater fish. Saltwater fish can live in the deepest depths of the ocean where no sunlight can penetrate, but they can also live on the surface of the water.[3]