Oceans cover 71% of the Earth’s surface and reach 11,000m at
their greatest depths. As such, the total volume of ocean water
habitat is 300 times greater than that of terrestrial habitats.
Comprising about 57% of the world’s 28,000 species of fishes,
marine fishes are a highly variable group of aquatic vertebrates
and include the hagfishes, lampreys, chondrichthyans (sharks and
rays), ray-finned fishes, coelacanths and lungfishes. Marine
fishes inhabit a number of ecological divisions including the
deep benthic waters, pelagic oceans, and shallow seas. The
greatest diversity of marine fishes is found in the Indo-West
Pacific region. You can tell a lot about where and how a fish
lives by the shape of its body. For example, tuna fishes are
ultra-streamlined torpedo shaped and are adapted for fast
swimming in the open ocean, whereas flounders have a flat body
and are adapted for living on the bottom of the sea bed. The
brightly coloured coral reef fishes are probably the most
popular group of marine fishes. Our